Showing posts with label VW. Show all posts
Showing posts with label VW. Show all posts

Thursday, November 3, 2022

Overactive Check Engine Light

AUTOMOTIVE RELIABILITY  

All automotive manufacturers have reliability issues with some or certain of their vehicles and Volkswagen is no exception even though it is one of the largest car manufacturer in the world. Globally the masses buy cars in general based on its looks (aesthetics), price, performance and reliability but not necessarily in that order.

In my opinion, reliability play a major role in decision making and should always be considered first. Hence, the question that begs to be asked is, "What's the use of owning a smart looking car with better than average performance that you acquired at a very attractive price but is as unreliable as a career politician". 

Understandably car manufacturers at times produce lemons (The Monday Car) or unknowingly fit a substandard part to some of the vehicles which only becomes apparent when it starts to fail in the field, necessitating a recalls. However, often times these troublesome parts slip through the cracks and fail infrequent enough and disparate enough as not to alert car owners to this pending problem and that is replaceable under recall. 


PCV valves

As a consequence car owners foot the repair bill for something that may never have been necessary to fix or replace if the manufacturer did their due diligence by adequately testing these parts before use. Any and all parts not tress tested or burn-in tested invariably fails and these failing parts then becomes known as Common Problems that plague the car owners.

Case in point, the Volkswagen Jetta 2006 - 2019 appears to have the most issues — aka Common Problems — necessitating seven (7)  major recalls due to some 295 complaints by owners to the National Highway Traffic Safety Administration (NHTSA). When these statistics are compare to the more reliable models, like the Volkswagen Golf GTI and the Tiguan which had absolutely no recalls and a very small number of complaints registered with the NHTSA, one notices the reliability factor.

MISLEADING DATA


This reminds me of how computer hardrives manufactures like Seagate, Western-Digital and Hewlett-Packard etc label hardrives by rating them at 1 Million hours 
 — MTBF (mean time before failure). One would be misled to believe when manufacturers as a whole guarantees the item/part in question for 1 million hours of operation before failure,. Whereas the said item has not even been in existence or production for this length of time, let alone tested for failure for this duration. One (1) million hours roughly equates to 114 years, so one can see how misleading that rating really is.

WHAT MTBF REALLY MEANS


Having said all that, I feel that MTBF is a really bad measure for determining the probable life span of any item, be it a hardrive, a light bulb, a printer, a TV, a car part or an entire car. However, what MTBF really means, is that if the manufacturer built 1 million units and started running burn-in test on all of them at the same time, one item is expected to fail per hour.  The same hold true for producing 5000 units, implying 1 unit will fail every 5000 hours. This is especially true for electronic components, its failure varying between the stringent implementation or slack specification and tolerances they are manufactured under. 

The German tradition and culture of manufacture in general gives rise to vehicles one can rely on with proven reliability and durability based on robust design, assembly, pride and attention to detail. This is noticeable on cars built and assembled in  Wolfsburg, Lower Saxony, Germany when compared to German designed cars manufactured/assembled elsewhere among which are South Africa, Mexico, Brazil, Asia etc. 

If your Volkwagen's VIN number starts with SN, ST or W you have a car that may outlast you whereas any other "world manufacturer identifier" prefix will virtually guarantee you a life of replacing parts. Purely because they are assembled from parts originating from ancillary OEM parts manufacturers and Chinese auto parts manufacturers instead of genuine VW parts originating from Germany.

Common Problems on Volkswagen vehicles mainly stems from these sub-standard rogue parts and several of them may be responsible for your Overactive Check Engine Light, from your leaking coolant, to excessive oil use and smoking, to engine overheating, to mention but a few.

EXCESSIVE SMOKING


Hard plastic has become the preferred product from which to manufacture modern day car spare parts —  in place of diecast aluminum machined to perfection —  and is used in abundance in most cars to reduce manufacturing costs, the overall weight of the vehicle that consequently improve its millage. 

However these plastic parts do become brittle over time thus prone to failure due to the engine heat. For example a blocked plastic PCV (Positive Crankcase Ventilation) valve  responsible for extracting the blow-by gases from the crankcase —  may be the cause of rough idling, poor acceleration and an increase in oil consumption and as a consequence excessive exhaust smoke. When detected by to O2 sensor will cause the Check Engine Light (CEL) to trigger.

OVER HEATING


Plastic thermostat assemblies commonly leak prematurely when they become contaminated by engine oil from a leaking PCV system. This may lead to that stubborn coolant leak that you cannot find  is more-likely-than-not caused by plastic pipe couplings, plastic hoses connectors, or perhaps the plastic radiator tanks located behind the AC condenser  that developed a minute crack, all able to cause overheating.



Wednesday, August 24, 2022

That EPC light

That EPC light.

The most likely reason you're reading this blog post, is because you encountered an EPC fault with your Volkswagen vehicle. I bet you wondered what that yellow/orange light was when it lit-up or perhaps startled when you car went into "limp mode". Whether you're driving a VW Polo or VW Jetta, VW Golf,  VW Caddy, VW Passat, T-Cross, Sharan, Touareg, Transporter, or any other Volkswagen or even a German Audi, or a Czech Skoda or a Spanish VW SEAT, you've come to the right place because they all have an  Electronic Power Control circuit. 



In fact all "modern day" vehicles have EPC circuit, which loudly says that the automotive industry have finally reached some consensus on standardization. But let me tell you what the EPC light actually is. It's just a signal light informing you that there is an error in your vehicles torque circuit. That's the short answer, however, I can tell by the look on your face that it wasn't a  satisfactory answer, so let me give you the long version.

The EPC light is part of the Electronic Power Control Circuit which is just one of the components of OBD-II which was mandated by a certain regulatory bodies with regulatory intent. Their initial intention was to limit carbon emissions / exhaust fumes from cars on the street of America. 

The California Air Resources Board (CARB) and the Environmental Protection Agency (EPA) together with the Society of Automotive Engineers (SAE) and the International Organization for Standardization (ISO) collectively originated the On-Board Diagnostic (OBD) System because of high levels of smog produced by automobiles throughout the USA.  

Their initial On-Board Diagnostic System was subsequently superseded by the all new and improved verion OBD-II, hence all cars manufactured post 1996 has an Electronic Power Control Circuit and by extension an EPC light. The European on-board diagnostics (EOBD) regulations are the European equivalent of the American OBD-II. 

On-Board Diagnostic (OBD-II) is an automotive mechatronic, micro processor / micro controller based computer system with programmed presets that continuously monitors inputs from numerous sensors fitted through the car. 

It then computes/compares/ compensates these inputs against stored data and drives various actuators to perform certain tasks. In a nutshell OBD-II is an input/output (I/O) information processing system much like the PC / laptop / or even your smart phone. By example, a keyboard, a mouse, a joystick, a scanner and a microphone are common computer input devices whereas a HD monitor, a printer, speakers and headphones are common computer output devices. 

Here the computer/laptop makes calculations based on its internal operating system and software to do something intelligible for humans. However in the case of OBD-II, its CPU (Central Processing Unit) is called an ECU (Electronic Control Unit) and among its input sensors are the Accelerator Position Sensor, Mass Air Flow sensor (MAF), Lambda O2 Sensor, Knock sensor, Oli level sensor, Coolant Temperature Sensor, the Camshaft Position Sensor, the Crank Position Sensor, the Wheel Speed  Sensor etc, to mention but a few.

Among its output actuators and solenoids are the drive-by-wire electronic throttle actuator, the fuel injectors, the EPC light, Malfunction Indicator Light (MIL), the Immobilizer, the Airbags and the Power Steering Pump, etc, again to mention but a few,

This ECU is sometimes referred to as an Engine Control Unit especially when intending to make reference to the TCU (Transmission Control Unit). The ECU is sometimes even called ECM (Engine Control Module) when making reference to other electronic control modules like the ABS module, the Instruments module, the Central Electronics Module, the CAN gateway module, the Radio Module, etc, again to mention but a few 

However, the ECU and the TCU are collectively referred to as Powertrain Control Module (PCM). The ECM essentially controls the efficiency of the engine performance by using a Crankshaft Position Sensor to determine the position of the cams in order to activate the injection of fuel into the cylinders and the timing of the ignition spark to ignite it at precisely the correct moment in petrol engines. 

Likewise the ECM in Diesel engines, plays a huge role in the success of the turbodiesel models. But in order for this to happen, an electronic throttle control had to be introduced, replacing the  cable from the pedal to the carburetor system which was prone to idle speed deviation between a hot and cold engine that became more and more prevalent as the components wore out. 

In so doing, the ECM can adjust the electronic throttle angle during acceleration to achieve the right quantitative relationship ratio between the actual airflow through the engine and the injected fuel thus maintaining Stoichiometry. Controlling the throttle airflow on the fly, markedly improves overall torque and driveability which is known as torque-mapping, an advantage that is only possible with drive-by-wire. 

So, the Electronic Power Control Circuit consists of the ECM, the Accelerator Position Sensor, the Throttle Position Sensors, the Throttle Actuator, the MAF / Air Filter, the Fuel Injectors, the High Pressure Fuel Pump, Fuel Temperature Sensor, Fuel Rail Pressure Sensor and Pressure Relief Valve. 

The single accelerator position sensor is made up of two individual potentiometers each acting independently of the other but collectively operate with opposite polarity voltages supplied by the ECM, as a safety back-up for one another. 

Thus, if either potentiometer fails, the ECM will activate limp mode. This is a safety measure that prevents the system from acting as if it had an accelerator cable that got stuck in the runaway position and the makings of a potential accident. The cruise control also has influence on the throttle body and requires the brake pedal to be depressed to cancel the cruise control. 

The ECU normally takes this cancellation signal from the brake light MOSFET low-side driver in the ECU. So either the brake pedal switch and the a brake light bulb can cause an EPC error along with the aforementioned fuel supply components. It's best to have a diagnostic tester to check for DTC errors via the DLC connector. It would at the very least steer you in the right direction to fix your EPC problem effectively.

Annoying VW EPC light

VW EPC expounded

As I've explained in an earlier blog, the amber Electronic Power Control warning light on your car's instrument cluster, is just an indicator light; drawing your attention to either (1)  an Auto-Correct EPC Problem, (2) a Pending EPC Problem, (3) an Existing EPC Problem or  (4) a Current EPC Problem. 

An Auto-Correcting  EPC problem occurs when the EPC light goes on without noticeable difference in engine performance and goes off during subsequent drive cycles which may be within a day or two or longer.

A Pending EPC Problem could be something as simple as a spark plug misfiring intermittently and appears in the scan list but after a while becomes an Auto-Correcting EPC problem alternatively if the plug continues to misfire it becomes and Exising EPC problem.

An Existing EPC Problem could be something like the MAF sensor or a accelerator pedal sensor that needs cleaning or replacement and a Current EPC Problem normally results in limp mode.



EPC light is bright YELLOW/AMBER and acts as a indicator, it is not as a warning light. 
Warning light are always RED.

EPC light is bright YELLOW/AMBER and acts as a indicator light, an advisory light; it is not as a warning light.  Warning light are always RED. Since the ECU "learns your driving style" over time, it records your optimize drive cycles to non-volatile memory along with atmospheric pressure, min & max rpm and the average fuel use data, etc, then creates an adaptive pattern or map based on these parameters. 

When this map is compared to sudden spirited driving, it may trigger the EPC light but will auto-correct (reset) itself after a few driving cycles within a day or two. Sometimes the EPC light may be accompanied by the Check Engine Light (CEL).

A Pending Problem can cause the EPC light to come and not switch off on its own. Pending implies that the problem will only get worse if left unattended to. A diagnostic scanner is needed to view the DTC error, hence its really worthwhile investing in one. 

For example, assume that cylinder number 3 randomly misfired a few times as the pending problem. The scan freeze frame data will show something like this.

000771 - Cylinder 3
               P0303 - 000 - Misfire Detected - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 2
                    Fault Frequency: 7
                    Reset counter: 255
                    Mileage: 38187 km
                    Time Indication: 0
                    Date: 2021.11.05
                    Time: 21:09:58


             Freeze Frame:
                    RPM: 758 /min
                    Load: 13.1 %
                    Speed: 0.0 km/h
                    Temperature: 51.0°C
                    Temperature: 33.0°C
                    Absolute Pres.: 830.0 mbar
                    Voltage: 12.435 V


What this means is that cylinder misfired 7 time, and that the most recent misfire occurred at the displayed time and date highlighted in red and has a fault priority of 2.  Fault priority of 4 or lower needs to be attended to immediately since it affects the driveability of the car. Don't ignore the VW EPC light.  

Fault priority of 5 and above doesn't require immediate attention but must be attended to sooner rather than later. The freeze frame date shows that the car was idling and 758 rpm with the speed at 0 kph and that the engine hasn't reach its optimum operating temperature as yet. In a nutshell, freeze frame captures the engine operating conditions at the time when the EPC error occurred.

An Existing EPC Problem could  mean either the throttle pedal, throttle body, or brake control unit or any other circuit related to the torque circuit, like the  cruise control unit or the traction control unit is misbehaving.  However the EPC light can also indicated an unrelated problem like a loose fuel cap. With the EPC light on, and a pungent fuel smell inside the cockpit would point you to fuel cap.  

Since the fuel is under pressure, the fuel pump, fuel regulator or fuel rail pressure sensor may also be suspect, each should be excluded through a process of elimination. Remember the Electronic Power Control system is integrated with several other systems on you vehicle, like the steering control unit and the ECU, hence it's not always easy to diagnose.

Its permissible to  drive your VW for a short distances and for a short period of time after the EPC light has triggered, that's to say if driveability hasn't been impaired but its best to either fix it yourself or take it to  VW service center. An  EPC dashboard light can be caused by any of the following, but in no particular order. Sometimes both the EPC light and CEL (check engine light) would turn on.

1) Brake Light Switch failure
2) Mass Air Flow Sensor failure 
3) Engine Speed Sensor failure 
4) Throttle System Potentiometer Failure
5) Cruise Control failure
6) Accelerator Pedal Potentiometer failure
7) Repeated cylinder misfires
8) Loose fuel cap
9) Blown / Faulty  brake light

Any of these can and may cause your vehicle to go into “limp mode” which can be described as a Current EPC Problem. When limp mode strikes, the Engine Control Unit will limits the functions of the torque circuit and transmission thus prevent your VW's engine from  revving higher than 2000 rpm and limit its speed to 30-45 kpm. 

Some mechanics would reset the EPC light by cleasing the DTC list without fixing the actual problem but this is not recommended. When the  Diagnostic trouble codes (DTC) are cleared,  "your driving style" map is also deleted, meaning that the ECU would have to relearn  "your driving style"  from scratch and your VW's performance may seem a bit off.  That's to say, until your racked up sufficient drive cycles (data) with which the ECU can do an analysis in real time. 

Monday, August 22, 2022

Grand Theft Auto

Grand Theft Auto

Volkswagen (VW) motor vehicles are not only popular among car enthusiasts, they  are also very popular car among the first-time car-buying youth. That said, VW vehicles have also become most popular car among car thieves to steal.

<a href='https://www.freepik.com/photos/car-thief'>Car thief photo created by freepik - www.freepik.com</a>


According the Crime Statistics Report for the years 2020 and 2021 - released by the South African Police Service (SAPS)- motor vehicle theft in general has steadily increased since 2011. However, it is correct thinking to assume that thieves have a preference to certain make and model of car.  Case in point - both the VW Polo hatchback and VW Polo sedan are at a higher risk of being stolen than any other VW model and other manufacture's vehicles as a whole.  

VW Polo Hatchback

Since its release in 2018 the VW Polo Hatchback had become the most stolen cars in South Africa. By 2019 it was the most sold passenger vehicle; targeted by "chop-shops" -illegal garages that buy stolen cars - to disassemble them and sell their individual components for profit - aka midnight spares. 

The new VW Polo hatchback - front-wheel drive, 5 door with 5 seats, powered by a 2.0L TURBO 4 engine that outputs 147 kW of power and 320 Nm of torque costs roughly between R320K and R480K whereas a older model or one with  a lower capacity can sell for anything from R170 000 and R250 000 subject to millage and overall condition.

VW Polo Sedan

The VW Polo sedans comes in as either Trendline, Comfortline, Highline and are essentially the sedan version of the  VW Polo hatchback with and engine capacity of either 63 kW  of 77kW fetching a price between R270k and R350k.

Insurance

Loosing a vehicle of this calibre with such a pricetag can be really gruesome hence a condition of any hire-purchase agreement to keep the vehicle adequately insured but an anti hijack immobilizer and alarm system is also essential. Car insurance coupled to Life Insurance may also be highly advantagious.


Anti-theft Alarm, Remote Central Locking and Remote Central Locking are not standard features of all models but the all do come with an Immobilizer but without Automatic Door Lock. It is therefore feasible to invest in an anti-Blocker, anti-Signal, anti-Jammer engine immobilizer with vehicle tracking GPS tracker support and engine cut in preference of the factory fitted product.

Transponder detection

Since most later vehicles are fitted with receiver and transponders chips, stealing a car without having its corresponding key is quite difficult.  If the key isn't close to the steering column stalk that houses the receiver coil or not within key detection distance then engine will not start.  Thieves also resort to key re-programmers and signal grabbers to counteract new technologies like ‘push to start’ buttons installed in the later model vehicles.

<a href='https://www.freepik.com/photos/car-thief'>Car thief photo created by freepik - www.freepik.com</a>

Carjacking

So, in order for thieves to steal your car they would have to take it from you by force  - hijacking, a horrific experience. Most cars today are stolen that way by hijacking the driver. If the thieves don't have the matching ignition key, the immobilizes prevents them from starting it by inhibiting the starting process, hence they take the car from the driver with key by force -carjacking. 

Safety Tips to prevent a possible hijacking


Before getting into your car, look around for any any suspicious characters. Should they be around alert a friend, family member or neighbour, even get them to accompany you.

Hijackings are often than not planned, so be be vigalent and cognizant of vehicles following you even at a distance.

Jot down the number plates of vehicles that or that continually pop up on your daily travels and check against previous ones.

Report any s suspicious activity to your local neighbourhood watch or security company of police.

Make sure that you are not being followed before driving into your driveway where you could be cornered.

Alert someone at home before driving into your driveway, to come outside to observe if there are suspicious characters lurking about.

Always be aware and alert of your surroundings before getting out of your car.

Never stop or park your car in a way that you cannot get away from someone following you quickly. 

Be aware of any vehicle blocking your driveway as you pull into it. Honk your hooter constantly to alert neighbours. It may be sufficient to scare them off.


Tuesday, January 4, 2022

Common OBD-II problems

Common OBD-II Problems

OBD-II has now been in our faces for a "Quarter Century" and even though it works fairly efficiently to control the hydro-carbon emissions in post '96 vehicles to some degree, it isn't as effective as some people would've liked, in terms of its diagnostic accuracy or as transparent and simplistic in its use to aid the layman.  On the flip side, many people with several mechanics among them completely abhors OBD-II and sees it more as a hindrance that a help and even add that they prefer cars not to have OBD-II. Since its inception, OBD-II has stymied mechanics globally, especially when the OBD-II system shuts down the engine and turns on the  EPC Light or Check Engine Light. And today, some 25 years later most car owners and mechanics still suffer fits effects yet endure the wrath of OBD-II. However, regardless of what we as lay people say, OBD-II is here to stay and we cannot wish it or will it away. 

Genuine Volkswagen Audi - Harness - 1KD971658
Genuine Volkswagen / Audi Harness Mfg Part #: 1KD971658

Personally I think OBD-II is a great in all aspects and incarnations however it has its drawbacks. OBD-II  does place car owners at a huge disadvantage and at risk when it fails. Purely because the problems are not evident but rather masked by the mysteries of electronics technology. This very often leaves them stranded and in a dangerous situations when stuck in the middle of nowhere. With the result that even the DIY car owners cannot do any repair work themselves, but have to resort to phoning  a salvage company to come  load their vehicle onto  a rollback.  Unless of course they have previously invested in a OBD-II scanner  and is able to check for DTC error codes.  But as the saying goes, "most people only lock the stable after the horse has bolted". 

Another drawback of OBD-II is that since car owners in general do not own diagnostic scanners; so they have to rely on some mechanic workshop or mechanical to tell them what problems they've encountered with their vehicle but only once its repaired. Considering most mechanics / repair shops repair OBD-II errors by substituting parts until the cause of the problem is  solved. Merely because they don't even understand the workings of OBD-II well enough to pinpoint problems with any great success. For most of us, this type of hit-&-miss approach comes as an un-bugeted expense, which most car owners can ill-afford especially after having to pay the exorbitant rollback cost.

I believe there are thousands more vehicle owners today, interested in their own vehicle's maintenance and there are even more inclined towards DIY repairs than ever before because of ODB-II. Their motivating factor being the high cost of automotive repairs vs the low cost of ODB-II diagnostic scanners. Albeit that the lower cost scanners bordering on cheap doesn't do such a fantastic diagnostic scan as their more expensive counter parts. 

NEW GENERATION CARS

Hopefully, the next generation of automobiles will be released with onboard diagnostic scanners incorporated directly into the vehicle's infotainment system. Seeing that these fancy units are comprised of  several discrete devices built into the same platform.  It's quite common for the average touch screen infotainment systems to have features ranging from  Built-in Bluetooth to Built-in WIFI which supports WiFi hot-spot broadcasting. Integrated phone connectivity for calls. Some even have rear view camera support. 

Others have fully fledged full-format 1080P video decoding, and USB functionality with multi-format audio and multi-band radio, coupled to dedicated dual voice-coil subwoofer and surround sound speakers. Not to mention Internet APP download capability.  Some include mirror and link for both Android and IOS Phones and a Global Positioning System (GPS) for navigation. All thanks to the magic of powerful multi-core processors and microprocessor embedded systems. 

I'd say adding an OBD-II scanner in place of one of these gadgets would be more beneficial 
So, throwing in a pretty decent quality OBD-II scanner into such a menagerie of tech wouldn't be such a biggie for car manufacturers and the cost wouldn't be prohibitively expensive either.  But since we not at that point in automotive evolution as yet, most DIY car owners have to rely on the handheld / smartphone diagnostics to scan their cars. 

Be that as it may. Very fortunately there are some common fault lists that would prevent you from having to go buy an expensive OBD-II scanner or go through the agony and trauma of having your car fixed by trial and error. Sharing  common automotive problems for the benefit of other, who are bound to experience the exact same problems in the very near future is a godsend.  Same model cars tend to have the same problems as others but invariable and inevitably those components will fail because obsolescence was part of its initial design. The same components used different model cars tend to fail in the same way and cause the same problems.

We've found that the most common OBD-II problems are associated with misfiring engine cylinders, problematic exhaust Gate Reticulation system (EGR), Oxygen Sensor (O2), Electrical Harnesses and fault Catalytic Converters. Many car owners are decating their diesel models, claiming better performance. But since OBD-II was explicitly introduced to control and reduce carbon emissions, removing it is not such a great idea. 

Genuine Volkswagen Audi  Harness - 1KD971658
VW / Audi Harness ES#: ES2993475  
 

COMMON FAULTS 

Erratically idling, or misfiring of bucking or  car goes into limp mode or starts and cuts out all result any one or more of the following error codes:-

P0105 - Manifold Absolute Pressure / Barometric Pressure Voltage supply
P0106 - Manifold Absolute Pressure / Barometric Pressure out of range 
P0107 - Manifold Absolute Pressure / Barometric Pressure Low Input
P0108 - Manifold Absolute Pressure / Barometric Pressure High Input
P0234 - Turbocharger Overboost Condition Control limit exceeded
P0235 - Turbocharger Boost Sensor (A) Control circuit  limit not reached
P0236 - Turbocharger Boost Sensor (A) circuit  out of range
P0237 - Turbocharger Boost Sensor (A) circuit  Low Input
P0238 - Turbocharger Boost Sensor (A) circuit  High Input
P0243 - Turbocharger Wastegate Solenoid (A) Open/Short Circuit to Ground
P0245 - Turbocharger Wastegate Solenoid (A) Low Input/Short to ground
P0246 - Turbocharger Wastegate Solenoid (A) High Input/Short to B+
P1154 - Manifold Switch Over Malfunction
P1155 - Manifold Absolute Pressure Sensor Circuit Short to B+
P1156 - Manifold Absolute Pressure Sensor Circuit Open/Short to Ground
P1157 - Manifold Absolute Pressure Sensor Circuit Power Supply Malfunction
P1158 - Manifold Absolute Pressure Sensor Circuit  out of range
P1400 - EGR Valve Circuit  Electrical Malfunction
P1401 - EGR Valve Circuit  Short to Ground
P1402 - EGR Valve Circuit  Short to B+
P1403 - EGR Flow Deviation
P1404 - EGR Flow Basic Setting not carried out
P1406 - EGR Temperature Sensor Performance range
P1407 - EGR Temperature Sensor Signal too Low
P1408 - EGR Temperature Sensor Signal too High
P1511 - Intake Manifold Changeover Valve - Electrical circuit malfunction
P1512 - Intake Manifold Changeover Valve Short circuit to B+
P1513 - Intake Manifold Changeover Valve2 Short circuit to B+
P1514 - Intake Manifold Changeover Valve2 Short circuit to ground
P1515 - Intake Manifold Changeover Valve Short circuit to ground
P1516 - Intake Manifold Changeover Valve - Open circuit 
P1520 - Intake Manifold Changeover Valve2 - Open circuit 
P1521 - Intake Manifold Changeover Valve2 electrical circuit malfunction
P1553 - Barometric/manifold pressure signal ratio out of range

Polo Highline 1.9 TDI (9N) 2005
16621 - Manifold Pressure / Boost Sensor (G31): Signal too Low
P0237 - 000 - -

Audi A5 (8T0) 2012 
4166 - Manifold Pressure / Boost Sensor (G31)
P0238 00 [039] - Signal too High

Audi TT 1.8L R4/5VT 
16622 - Manifold Pressure / Boost Sensor (G31): Signal too High
0238 - 35-00 - 

000568 - Manifold Pressure / Boost Sensor (G31): Signal too High
P0238 - 001 - Upper Limit Exceeded - MIL ON

Passat 2.0T R4/4V TFSI 2006 
000568 - Manifold Pressure / Boost Sensor (G31): Signal too High
P0238 - 001 - Upper Limit Exceeded - MIL ON

VW Touran 1.9 TDI
P0236 - Manifold Pressure/Boost Sensor (G31) - Range/Performance Problem/Implausible Signal
Malfunction Indicator Lamp (MIL)(K83) active.

VW Golf 7 1.6TDI 
16622 (P0238 ) - Manifold Pressure/Boost Sensor (G31): Signal too High
16618 (P0234) - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)

Passat 2.0T R4/4V TFSI 2006 
004759 - Pressure Drop between Turbo and Throttle Valve
P1297 - 001 - Upper Limit Exceeded

This MAP Manifold Pressure Sensor aka Boost Sensor aka Thrust sensor  aka G31 is just a  thermistor. Essentially a resistor of a special kind, with the ability to change its resistance  subject to its surrounding temperature, hence the term thermistor is just a  word combination of "thermal" and "resistor".  However G31 sensor may not be fault but rather the wiring harness. Due to the constant engine heat, the harness wiring gets hard and becomes brittle resulting in poor contact, short and open circuits. 

FYI - Thermistors essentially come in two varieties, viz NTC (negative temperature coefficient) and a PTC (positive temperature coefficient). You can quite simply use an ohmmeter to measure the resistance of the thermistor. Then by bringing a hot soldering iron  tip close to the thermistor, its resistance would change in response to the soldering iron's radiated heat. When the resistance increases its a PTC and an NTC when the resistance decreases.  Much like discrete component resistors that are colour coded, thermistors leads are also colour coded which identifies the temperature range they operate at.

CATALYTIC CONVERTER

Catalytic Converter have become a hot topic of late. Thieves are stealing Catalytic converters from parked cars at night. However the Polo Highline 1.9 TDI is known to be troublesome. The main reason for  this being, use of poor quality diesel (500ppm as opposed to 50ppm or even 5ppm) and irregular oil changes  which caused soot build-up to block the performance of the catalytic converter, which in turn may lead to turbo failure.  So its fair to say that it's  not uncommon to remove/replace blocked catalytic converters  to prolong the life of the turbo itself.

However if it's not the Catalytic converter itself causing the above error,  it very possibly not the sensor either even though the diagnostic software may indicate that.  I'd say rather check, repair or replace the wiring harness to the Boost Pressure Sensor (G31) and also check wiring to the Intake Air Temperature Sensor (G42).  See my previous blog post https://volkswagen-polo-highline.blogspot.com/2015/03/wiring-harness-issues.html 

The diagnostic scanners may also thow the following errors in conjunction with the error above,  which could be caused by a leak in Air Intake and or Exhaust

16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal
P0106 - 35-00 - -

18000 - Altitude Sensor / Boost Pressure Sensor: Implausible Correlation
P1592 - 000 - -

Diesel engines are quite different from petrol engines in the sense that  the diesel engine is not variable in speed or power by controlling the air entering the engine as we do with the  throttle body in petrol styled engines. Feedback from Catalytic converter in petrol engines are also used to adjust the short term and long term fuel trim. Implying that petrol cars also have turbo boost errors due to the cat and intake and exhaust sensors.

16485 / P0101 Mass Air Flow Sensor (MAF) (G70) = Circuit Signal Implausible (out of range)
16497 / P0113 Intake Air Temperature  Sensor-1 (G42) = Signal too High
16515 / P0131 O2 (Lambda) sensor low voltage =  Bank-1 Low Voltage
16584 / P0200 Injector circuit =   Injector Circuit electrical fault
16620 / P0236 Turbo / Manifold Pressure Boost Sensor (G31) = Signal Implausible (out of range)
16622 / P0238 Turbo / Manifold Pressure Boost Sensor (G31) = Signal too High
16683 / P0299 Turbo Boost Pressure Reg = Control Range not reached (underboost) /mechanical fault
16785 / P0401 Exhaust Gas Recirculation (EGR) = Insufficient Flow (blocked)
17055 / P0671  Glow Plug/Heater Cylinder 1 (Q10)  electrical fault, open circuit 

17958 / P1550 code = Charge Pressure Control Deviation
Check for air leaks on both intake or exhaust side 
Turbocharger - check for whining engine and exhaust smoke
Charge Air Pressure Sensor faulty  - check connection to one of the the intercooler pipes
Wastegate Regulator N75 Valve  faulty  - Check one of the 3 thin hoses for leaks

18534 / P2102 Throttle  Actuator Control Motor = Signal too Low, check voltage to accelerator pedal 
18675 / P2243 O2  Sensor Reference Voltage Bank 1, open circuit 

___________________________________________________________________

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Saturday, December 26, 2020

Electronic Vehicle Architecture

Electronic Vehicle Architecture

The Electronics  Industry has had the fastest growth in the shortest amount of time, when compared to any other industry worldwide.  But before I expound on that, let me just say that, the invention of numerous mechanical contraptions during the late 1800s, like  James Watt's steam engine for example, started the transition towards new manufacturing processes which collectively gave rise to thIndustrial Revolution. Much later Samuel Finley Breese Morse invented the single-wire electric telegraph system and developed the Morse  Code. 

A bit of History

Sometime thereafter Alexander Graham Bell invented the first practical telephone system. Their's and the collective  efforts of so many others, without discounting anyone's  inventions and efforts, changed telecommunications forever. Ancient records show that  the first streets of Baghdad were paved with tar, that the Babylonians used asphalt to construct the walls and towers of Babylon.  The I-Ching even bears testimony to the fact that the cites of China used oil, extracted in its raw state some  2000 years ago before refining was first  discovered. Implying that the petroleum industry is not new, but that the current status of petroleum is a key component of politics,  technology and society today.

No tot digress, tar, crude oil and pitch, were used as a sources of fuel long before paraffin was even distilled from it. The thin distilled  paraffin was normally used as fuel for lamps whereas several hundreds of years later, the thicker residue was used to lubricate machinery. In and around the  time when oil/gas/fuel/petroluem was extracted from coal, Étienne Lenoir successfully built the internal combustion engine and innovated by Nikolaus Otto, who became famous for successfully developing the compressed charge internal combustion engine - the Otto engine.  

Assembly lines

Henry Ford on  the other hand wasn't an inventor nor an innovator as many have been led to believe, but he was rather a business magnate and a captain of  industry, who formed the Ford Motor Company, and sponsored the development of the "assembly line technique" for vehicle mass  production. One can therefore confidently say that their combined efforts, without diminishing any other contributor's efforts by the very least, over a period of some 200 years, are partially responsible for the social changes and economic development that shaped  societies that we live in today. This was  the infancy of the Automotive industry.

However, compared the Industrial revolution, modern day electronics would be equivalent to a Global Coup. Initially there was the  vacuum tube aka the electron tube, colloquially known as a valve. It gave way to the trusty transistor and discrete components which gave rise to the  analogue Integrated Circuit (IC) aka chip, followed by digital Transistor/Transistor logic (TTL) chips, followed by complementary  metal oxide semiconductors (CMOS), then digital semiconductors like ROM (digital read only memory), RAM (random access memory),  EEPROM (electronically erasable programmable read only memory), followed by large scale integration chips and VSLI (Very Large Scale  Integration Chips). 

Electronics and Software

With the advent of multilayer circuit boards and surface mounted technology, microcontroller SoC (system on a chip)  and microprocessors (µP) became pervasive. Assembler language was superseded by several high level languages for programmable chips and  software programming sat at the heart of most electronic devices and electronic systems. All of this happened in 50 years of electronics  as opposed  to 200 years of mechanical devices.

So you may ask, what has all this history to do with Volkswagen, Audi, Seat and Skoda and for that matter all other modes of transport  from plans to trains? Well the short answer, everything! Much like the Industrial Revolution with its mechanical ingenuity;  cars and planes were also predominantly mechanical since its inception, its mechanical ignition system was prone to imprecise ignition timing, resulting in improper fuel mixture burn, thus increasing its exhaust pollution. 

With the rise of telecommunications, so did  the electric wires, and electrically controlled gauges, relays and switches in cars and planes multiplied. The ever inflating cost of  gasoline then triggered the invention of CDI (Capacitive Discharge Ignition systems) which is in fact the first type of electronic  contraption integrated into the ignition system of a vehicle in order to, more precisely control its ignition timing, making it more  fuel efficient. 

These devices were available as add on kits and not produced as standard equipment in cars at the time. The preferred standard  equipment was the IDI  (inductive ignition system) and is the most common ignition system found on all cars built prior to 1980. It used a coil and distributor incorporating breaker points in its ignition system that was prone to ware-out due to arcing on  contact. During the 80's engines still used a coil and distributor to achieve dwell but it was somewhat computer controlled and by  the 90's the automotive computer evolved to ignition modules and the ECU, replacing the coil with a power pack. 

However, with the constant and  ever increasing price of gasoline and looming environmental concerns centred around vehicle exhaust pollution, the automotive  industry then accelerated its research and development into newer more compact fuel efficient power-train systems capable of higher  power output with enhanced robustness with a open policy towards alternative fuels.

New generation cars

So, by the 90's the Insulated-Gate Bipolar Transistor (IGBT) was introduced into the ignition system as discrete component connected  to the ECU called OBD - On-Board diagnostics. By 1993 the CAN protocol was standardized by ISO which led to its increased popularity  and adoption across the automotive industry.  By 1996 OBD had evolved to OBD-II and the discrete IGBT evolve into a IGBT module  integrated into individual coils itself. Starting from Y2k ignition systems were all ECU based but power packs were replaced by a  dedicated coil per cylinder, yet cloning the use of an Insulated-Gate Bipolar Transistor (IGBT) as discrete component connected to  the ECU. 

Communication Buses

From 2004 to 2010 the discrete Insulated-Gate Bipolar Transistor (IGBT) integrated into individual ignition coils evolved to a smart IGBT alongside the ECU.  The automotive ignition system had undergone a complete revolution which contributed significantly  to the system’s efficiency, exhaust pollution reduction, and robustness. By which time the use of wires had been minimized in  preference of a bus network which supported vehicle weight reduction and  vehicle cost. Copper wire have been replaced by fibre optic cable to facilitate faster communication. Some of the most important bus communication systems are CAN-Bus, Lin-Bus, MOST and  FlexRay.

Actuators and sensors, electronic control modules, Can-Bus and the ECU collectively facilitating Electronic Power Control (EPC) aka electronic throttle  control (ETC), Electronic Exhaust gas reticulation (EEGR), Electronic Valve Control (EVC), Electronic fuel injectors and so much  more, are just a small part of the overall influence that electronics have had on all vehicle engines. Other subsidiary programmable electronic  modules which are smaller computers in their own right now permeate cars, bikes, planes and boats, all connected together by at least three network systems. 

CAN-Bus is a multi-master twisted pair wire system reserved for high speed control systems like brakes,  whereas LIN bus is a single master, single wire system for low level communication for use by the rain sensor, sun roof, internal heating, and  the infotainment-bus, is a slow-speed system reserved for radio, GPS, internet communication, etc. Each system communicating with each  of its nodes in its provided protocol, each having different data transmission rates. By incorporating this level of electronics into cars, it has vastly improved stichometry and overall engine  performance, its economy, its driveability  and its safety besides reducing  emissions. 

Inept electronic knowledge

However, few mechanics know sufficient about electronics with its combinational logic, digital multiplexing, bits and  bytes, start and stop bits, fixed frames, software, etc to repair these cars packed with intercommunicating electronic modules. Even though scan tools have vastly increased their chances at successful repair, not knowing how to interpret fault codes further disadvantages them, not to  mention how frustrating it is for the vehicle owner who gets stuff around by incompetence. And here I’m even refereeing to the  "Automotive Technicians" employed by their respective automotive agents, who are more often than not incapable of repairing vehicles fitted with OBD-II. I'm quite sure there are several hundred if not thousands  of  VW owners who would concur.  How is it even expected for the DIY mechanic to fix it him or her self if the agents can't. Needless to say that  with continuous improvements comes great complexity and their successful  strategy to part us with our hard earned monies.

Diagnostic Trouble Codes abbreviated as DTC have been around for approx 30 years and is a component of OBD-II (onboard diagnostic system ver.2). These codes can be found stored  in the ECU's non-volatile memory for later retrieval by way of a scan tool. DTCs are displayed specific to the kind of problem that the system can or does detect from inside of a car engine/transmission, chassis, body or network.

Scan codes

In reality DTC codes can assist "automotive technicians", DIY mechanics and car owners to understand the problem with the car and possibly point them towards the nature of the problem or at the very least the system concerned. Bearing in mind many DTCs are generic but many of them are manufacturer specific and is best interpreted by consulting the car's manual.  Generic codes are defined by the EOBD / OBD-II standard and will therefore be the same for all car manufacturers.

But, let me break it down to for you. All diagnostic codes are alphanumeric as in P0XXX. It start with a letter followed by 4 numbers, as in P0303. This initial letter is P but can also be either B, C or U. They stand for Powertrain, Body, Chassis and Network respectively. The first numeral following the letter signifies whether the fault is generic of manufacturer specific. Since its a 0, its a generic code but if had a 1 then it would be manufacturer specific. The number 3  following the first 0 can be any numeral between 1 and 9. This number directs you to the subsystem of the car and is as follows.


Px1xx Air and fuel metering
Px2xx Air and fuel metering
Px3xx Ignition system and misfires
Px4xx Auxiliary  / additional emission control
Px5xx Speed control and idle regulation
Px6xx Communication /computer output signals
Px7xx Transmission
Px8xx Transmission
Px9xx Control modules, input and output signals

The final two numbers (xx) designate the individual components / sensors /actuator that threw the error. For example P0300 says, it's a powertrain error, it's generic in nature, it's in the ignition system and it's a random misfire. 

Whereas P0301 says misfire by cylinder No. 1,
Whereas P0304 says misfire by cylinder No. 4,
Whereas P0308 says misfire by cylinder No. 8,
Whereas P0312 says misfire by cylinder No. 12,

Likewise P0403 says, its a powetrain error, it's generic in nature, it's in the auxiliary / emission system and that the "Exhaust gas recirculation control malfunctioned"

Likewise P0501 says, its a powetrain error, it's generic in nature, it's in the speed control/regulation circuit and it's the "Vehicle speed sensor is out of range".

Like wise P0656 says,its a powetrain error, it's generic in nature, its in the computer/communication system and that its the "Fuel level output electrical sensor/circuit" 

Then there are also VAG specific 5 number numerical codes that coincide with P,B,C and U codes, like 16692 which coincides with P0308 (Misfire Detected on Cylinder 8)

And 17026 which coincides with P0642 (Knock Control Control Module Malfunction)

Monday, June 8, 2020

VOLKSWAGEN HACK

VOLKSWAGEN  HACK

Since the inception of OBD-II car manufacturers were mandated to install immobilizers on all vehicles built from 1996 onward. The preferred technology used by more than a dozen vehicle manufactures which includes Audi, Volkswagen, Volvo, Fiat, Honda and Chevrolet, was the Magamos Cryto transponder, viz ID48. A passive glass RFID chip used for authentication and preventing hot-wiring, embedded in the keys of these vehicles had a vulnerability. Electronic vehicle immobilizers in general have been very effective at reducing car theft to date, but today some 24 years later virtually each and every car immobilizer manufactured is defunct and the security they provide is worthless because its been hacked. 

This vulnerability in automotive security was cracked as long ago as 2013 by computer scientist Flavio Garcia and a team of researchers at the University of Birmingham. By implication they suddenly had access to a 100 000 000 Volkswagen vehicles across the globe. However, before they could publish their research to general public consumption, they were hit with a lawsuit which caused a two year delay but their paper was eventually publisized.  Their article reveals numerous weaknesses in the design of the cipher, the authentication protocol and also in its implementation allowing them to gain eavesdrop on authentication traces. This was sufficient  to recover the 96-bit secret key with a computational complexity of 256 cipher ticks and the secret key after 3 × 216 authentication attempts. This was all achievable in under  only 30 minutes. 

This all came about when local police was baffled that cars were being stolen and nobody could explain how. But they suspected that the thieves  used some kind of ‘car diagnostic’ device to bypass the immobilizer and start a car without a genuine key. In order to solve this mystery Flavio Garci and his researchers  were motivated to evaluate the security of vehicle immobilizer transponders. At the time it was commonly known hack attacks for other widely used immobilizer transponders, viz DST40, Keeloq and Hitag2 though  not much was known about the vulnerabilities of the Megamos Crypto transponder.

The Megamos Crypto transponder has since been cracked by the university team in their attempt to discover how "the thieves did it'' and realized how easy it was. This speak volumes about the technical, cryptographic, algorthmic, code cracking software savviness of the thieve who figured it all out even before the scientist and his team.

So now a team of researchers from the University of Birmingham and a German engineering company viz. Kasper & Oswald intent revealing two distinct vulnerabilities they say affect keyless entry systems. Using these two vulnerabilities resourceful thieves would be able to wirelessly unlock virtually every vehicle that  Volkswagen manufactured during the past twenty years.  These include  cars from manufacturers like Alfa Romeo, Citroen, Fiat, Ford, Mitsubishi, Nissan, Opel, and Peugeot. 

No car with the most sophisticated immobilizer built during this time is immune to evaporate in the middle of the night, unless protected by old school brute force, steering and gear locks, parked inside a garage protected by half a dozen pitbulls.

FOB key

FOB key Tips and Tricks


With the advent of electronics, life for many has become somewhat easier and high-tech. Case in point, the trusty television cordless infrared remote control and its earlier ultrasonic equivalents. Both circumventing the "jack in a box" activity we all so enjoyed, during the days of legacy non-remote control television sets. Likewise, our cars has also gone high-tech, flaunting electronic car key remote controls with features never seen before. No longer using infra-red or ultrasonic but a coded signal modulated in a wireless radio frequency in the 315 to 434 mhz range.  

Not only has remote controls replaced the aim push and turn function our writs won't forget but has gone far beyond locking or unlocking doors, remotely starting the car,  emitting chirping sounds with flashing hazards to assist us to find our car in a fully populated parking lot. These fancy electronic remotes control marvels are referred to as a "fob", an acronym for Frequency Operated Button. In a previous lifetime, a "fob" was the name given to the chain connecting a packet watch to its owner. Today the "fob" is form of invisible tether, chaining the remote to the car. Some say the word "fob" comes from the German word Fuppe, meaning pocket. I suppose that's where its going live when its not on the car. 


Manufacturers are constantly adding more features to the already multitude of functions that make both the car and the key "fobmore useful than ever before. But its not all done in the name of the client. It has allowed manufacturers skimp of a few items that drove the price of the car up ever so slightly. Fobs allowed them to only install a single driver-door key cylinder, thereby saving on the cost of the other three, the installation time and somewhat reduced the weight of the car, alongside so many other items.  Collectively contributing to its overall fuel economy. But the quality of this driver's door cylinder isn't design nor manufactured robust enough and daily use. It's intended for emergencies only use, when the key is either locked inside the car or the battery had died of the "fobhas gone faulty. Using it daily will kill that lock before you can fluently say, Rumplestillhurrywisepunywalgeemuckagee.

VW button mechanically operated switch blade "fobcomes in 2 basic flavours -- 2 button and 3 button.  One buttons specifically  for lock and the other for unlock. Keeping the button depress for a few seconds activates windows either open or close whichever is needed.  A flashing LED on the remote denotes communication.
Depending on the ECU/ control module settings, button depresses can be either audible or visible or both. Meaning a peep or two from the hooter and single or double flashing of the hazard light, or nothing based on personal preferences.  In the case of a 3 button, much like the 2 it just has a 3 for trunk release. In those vehicles with an auto lift trunk piston feature, pressing the unlock button will is open the trunk completely. 

The "fob" is a sophisticated piece of equipment but when it misbehaves, and you have to make multiple attempts before it performs a function, it could be that the battery is going flat. This is easily verified by viewing the intensity of the blinking LED on the "fob". A faint LED is a tell tail sign the the battery is giving up the ghost. When the battery is replaced, the "fobneeds to be reset. This can be done by pressing the lock one second while the car is locked. Nothing will happen except perhaps a low volume yet mechanical clunk. Remove the cylinder cover, unlock and re-lock your your car with the master-key, not spare key. This action will cause your "fobto reset itself.

When the car wont start and the light is flashing the key, keep it close to start button to make reading the key easier so that the car will start. VW Tiquan and some other later VW's allows  "fobsynchronization and reprogramming of driver preference like, radio stations, mirror positions, etc.  Since a detailed rundown of the procedures are beyond the scope of this post, your owners' manual is by far your best bet. 

Tuesday, January 15, 2019

VW Fuses Switches and Relays

VW Fuses  Switches and Relays

Single Pole Single Throw

Electrical switches comes in several configurations, but are normally classified into only four types. The most common switch is the single pole single throw, abbreviated as SPST. This implies it has one contact that is normally open —abbreviated N/O—  which is closed when the switch is flicked. This type of switch is either on-or-off / open circuit or closed circuit. This switch also comes in the form of a push button switch which is normally open and closes when pushed but when released it open once again. It is also known as push-to-make, abbreviated PTM. An example of a PTM is a door bell switch or a cars hooter or the individual keys on a keyboard. Push button switches also comes in a normally closed configuration and opens when pushed, but when released, it closes again. Commonly  known as push-to-break, abbreviated PTB. An example of a PTB switch is used to release a door, held closed by an electromagnet.

Suzuki GS500 GSXR1100, Honda  VT 500 VT600 VT700 VF750,
Kawasaki ZX1000 ZX 1100 Solenoid


Single Pole Double Throw

The second and slightly more advanced switch is the single pole double throw switch, abbreviated as SPDT. This is a three terminal switch which toggles between two states when switched. SPDT are in essence two switches in one package. The one switch is normally open whilst the other is normally closed. By flicking the switch the two switches reverses their roles. The normally open switch is then closed and the normally close switch is opened. By connecting a SPDT at either end of a long passage to turns the lights or off, one is able to enter the passage at one end, turn the lights on and when exiting the passage at the other end switch the lights off. SPDT can be used as a SPST in an application by just using the centre contact and either one of the other two contacts, depending on what type of switch you need, N/O or N/C.  SPDT switches are also available with a centre-off position, known as momentary (ON)-OFF-(ON) switch.


Volkswagen 4H0951253 Starter Relay 645 and 1J0906381A Fuel pump relay 109. 


Double Pole Single Trow

The third type of switch is the DPST and is similar to the SPST switch in operation except that it has a pair of on-off switches that switch together. It is commonly used to connect / interrupt both the live and neutral supplies in a circuit simultaneously or it may be used to switch two separate circuits simultaneously. Computer power supplies have DPDT switches as a safety feature to avoid getting electrocuted whilst working on the power supply if only one pole was switched. 


Double Pole Double Throw

The fourth type of switch is the DPDT and is similar to the SPDT switch in operation except that it has a pair of on-on switches that switch together. It is commonly wired to reverse the direction of a DC motor or be used to switch between to different colour LEDS. DPDT can be used as a DPSP in an application by using the centre contact and either one of the other two contacts and duplicated on the paired switch. DPDP switches are also available with a centre-off position, known as momentary (ON)-OFF-(ON) switch.




Switches 

Switches switches come in various shapes among which are Toggle switches, limit switches, reed switches, micro switches, mercury switches, rotary switch, slide switch, rocker switch, pneumatic limit switches, selector switches and getting the right switch for the job cam sometimes be tricky and may be better suited by using a relay. Many switches also come with a rubber jacket to make it  waterproof. However that doesn't imply you can submerse the switch in water, it is more a splash proof cover than a water proof one. There are switches suited for using under water, for example a floating mercury switch. when a vat or tank is filled with liquid, the switch would float in the upright position but when the liquid falls below a certain lever  the switch would float upside down and trigger. Perhaps turning on a pump that would fill the tank or vat once again.


Whats a relay?

Having discussed switches you may ask what does switches have to do with relays. The simple answer is, a relay is essentially a remotely controlled switch. Relays are controlled electrically rather than mechanically, hence they're known as electro-mechanical relays. They are commonly used in automotive design, where high current devices can be switched from a cockpit fairly cheaply. In stead of using long lengths of thick high current cable and a substantially heavy duty on-off switch to control a heater or a motor situated some distance from the driver; a small low current switch and a length of thin low current cable and a relay switch with heavy contacts would suffice. Every relays has a solenoid configured as an electromagnet. So when the solenoid is activated by a trigger voltage, the electromagnet pulls a set of heavy duty contacts to make or break a circuit. Relays are versatile and can function as a simple spst switch, or a more advance spdt switch of a dpst switch or a dpdt switch depending on the circuity it needs to control.





Volkswagen Solenoids

Sometimes you may need a switch with more contacts than the best switch you can find, and this is where relays outweigh switches. Relays also cost less than the combines cost of all the switches that it replaces or that can do the job of.  Volkswagen have several relays throughout its electrical system and the most hardworking relay, is the starter relay.  Starter relays form part of the starter, the reasoning, is to keep high current conductors as short as possible. However many cars have a second relay inserted into the fuse panel that powers the starter solenoid. So when you turn the ignition key to start your car, the starter relay contacts in the fuse box sends 12V to the starter solenoid on the starter. This solenoid's contacts throw and sends 12V from the thick battery cable that's connected to one side of the starter solenoid directly to the starter's field coils, causing its armature  to spin. But at exactly the same time the solenoid performs a dual function as it kicks the bendix forward into the ring gear's teeth.  The starter's force of rotation is sufficient to crack the engine and if all's well, the engine with start.