EPC DEMYSTIFIED CONTINUED 2

Continued from EPC DEMYSTIFIED CONTINUED 1.

  ...  I only became aware of this when my EPC light went on due to the knock sensor. See picture blog.  More...

 PART 3

BREAKING THE CODE

What needs to be mentioned as a basis of understanding, is that OBD (on-Board Diagnostics) was introduced in the 70's along with CDI (capacitive discharge ignition systems) as DIY kits. Few cars had fuel injectors, points and coils were fast being taken over by electronic modules. During this time some standards were introduced but they were not very well defined and as such manufacturers developed their own and applied their specific systems and developed their own code descriptions which later became known as OBD1. This was considered undesirable and counterproductive since none franchised service, and general mechanical repair centers had to purchase different scan tools, interface cables and connectors, skills and manuals for each make and model of car they specialized in. This resulted in vehicle diagnostics becoming unwieldy expensive. In February of 1986, Robert Bosch founder of Bosch, introduced the CAN (Controller Area Network) serial bus system to  the Society of Automotive  Engineers (SAE) in motor town of Detroit.

This influenced the  Society of Automotive  Engineers (SAE) who subsequently drafted a list of standards and practices that aught to be implemented by all automobile  manufacturers and recommended them to the Environmental Protection Agency (EPA). The EPA weighed-up these standards and recommendations, acknowledged their benefits, and adopted them. The standards criteria included a precisely defined diagnostic connector for each auto manufacturer, a standard scan tool and a common electrical communications protocol and a common data format, and the ability to monitor other
vehicle parameters. Lastly that the standard scan tool should interface with vehicles of all manufacturer. It also included mandatory definitions and descriptions for certain emission control system  defects which was labeled the ‘P0’ Codes. Manufacturers were allowed to generate and use their own ‘manufacturer specific code descriptions’ known as ‘P1’ Codes. This collaboration of standards became known as OBDII, (OBD2) and was adopted for implementation by January of 1996. Two types of scanner codes, namely manufacturers codes like VAG codes and SEA Codes are now the standard practice.

OBD-II  

As mentioned above, Powertrain Control Module (PCM) error codes are assigned the prefix P and pertain to the, Engine management, Transmission management, Fuel Pump and Gasoline Management, Automatic Transmission – Hydraulic Control, Emission control system, evaporative emission purge control (HVAC), Auxiliary module management and other some 0n-board Hybrid application.  For example P1340  suggests that the Powertrain triggered a DTC and describes it as an "Crankshaft-/Camshaft Position Sensor Signals Out of Sequence"

From the above example it would thus be easy to interpret the DTC below relating to EPC (Electronic Power Control)

DTC (VAG)   DTC (SAE)  Society of Automotive  Engineers

16504 P0120 Throttle Position Sensor A - Circuit Malfunction
16505 P0121 Throttle Position Sensor A - Circuit - Performance Problem - Out of Range
16506 P0122 Throttle Position Sensor A Circuit - Low Voltage Input
16507 P0123 Throttle Position Sensor A Circuit - High Voltage Input
16894 P0510 Throttle Position Sensor - Closed Switch- idle micro-switches -F60 malfunctioning
17951 P1543 Throttle Actuation Potentiometer - Signal too Low
17952 P1544 Throttle Actuation Potentiometer - Signal too High
17913 P1505 Throttle idle micro-switches -F60 not/short-circuit opens
17914 P1506 Throttle idle micro-switches - Switch Does Not Open/Short to Ground
17988 P1580 Throttle Actuator (B1) Fault - May be caused by low battery if found with 16487 (P0103)

18038 P1630 Accelerator Pedal Position -G79 signal too small  (low)
18039 P1631 Accelerator Pedal Position -G79 signal too largely (high)
18040 P1632 Accelerator Pedal Position -G79 supply voltage malfunction
18041 P1633 Accelerator Pedal Position -G185 signal too small
18042 P1634 Accelerator Pedal Position -G185 signal too largely
18047 P1639 Accelerator Pedal Position 1+2 Range/Performance -G79 and -G185 implausible signal
18048 P1640 Internal Controller Module defective (EEPROM) Error

EPC Circuit.

The EPC  circuit consists of a number of disparate components that control and supervise, regulate and determine the throttle valve position at all times. They include;

1) the accelerator pedal position sender (TP sensor G69)
2) the accelerator pedal position sender -2, (G185)
3) Black 6-pin plug with 6-pin with Gold plated contacts

NB! The above three components are part of the accelerator pedal.

4) the throttle valve control module (unit),
5) the K132 EPC fault lamp, (electronic throttle control fault indicator)
6) the engine control module (unit).

Firstly we going to do a test on components 1, 2 and 3 above. To do this test, you need a Fluke multimeter or similar for a voltage and continuity / resistance test. Unplug the 6-pin plug from the accelerator pedal and switch on the ignition. Connect the multimeter and check for a 4.5 volt reading between;-

pin 1 and ground, then between pin 1 and pin 5
Pin 2 and ground, then between pin 2 and 3.
If tests prove to be "OK", switch ignition off.
Do additional checks for short circuits between one another and ground and if this checks "OK",

Locate the ECU, normally inside cowl. Disconnect the ECU from its socket, identify pins 34 & 34, 35 & 36, and 72 & 73 on the socket. Disconnect the 6-pin plug from the accelerator pedal once again and check for continuity between this plug and the ECU socket. There should be continuity between pins:-

1 of the 6-pin plug and pin 72 of the ECU socket.
2 of the 6-pin plug and pin 73 of the ECU socket.
3 of the 6-pin plug and pin 36 of the ECU socket.
4 of the 6-pin plug and pin 35 of the ECU socket.
5 of the 6-pin plug and pin 33 of the ECU socket.
6 of the 6-pin plug and pin 34 of the ECU socket.

Any resistance above 1.5ohms should be investigated for corrosion. This often causes the engine to surge (idle unevenly or rather breaths) However, if this test proves "OK" and no wiring malfunction is detected, replace G69 and G185 (single unit) on the accelerator pedal. NB! these components are non adjustable and needs to be replaced as a whole.

When the ignition is turned on, the ECU checks all EPC components necessary for the proper  functioning of the Electronic Power Control. If a malfunction is detected in the EPC (Electronic Power Control) system whilst the engine is running, the ECM will simultaneously activate the EPC (Electronic Power Control) warning light and make an entry of this malfunction in  the ECU (electronic Control unit) DTC (Diagnostic Trouble Codes non-volatile memory.  By a process of eliminate the EPC fault can be fixed.

The list below categorises VW and Audi manufacturer predetermined data groups which varies depending on the vehicle, year, engine, engine code and management system on board.

Group Number / Group Category

1–9     General engine activity data
10–19 Ignition data
20–29 Knock control data
30–39 02 sensor control system data
40–49 Three-way CAT data
50–59 Engine speed control data
60–69 Throttle drive data
70–79 Emissions reduction data
80–89 Special function data
90–97 Power increase data
98–100 Compatibility data
101–109 Fuel Ignition data
110–119 Boost pressure control data
120–129 Control unit communication data
130–150 Special info data

Based on the data from the above table EPC problems are associated with group 60-69. However, on Expert Systems Diagnostics Group 60, holds the EPC Adaptation data, group 61 holds EPC-system 1 data and group 62 holds the EPC system 2 data. Group 66 holds the speed-o-cruise data.

NB! If you found this information useful, please link to this page.

EPC DEMYSTIFIED CONTINUED 1

Continued from EPC DEMYSTIFIED.  

  ....But it’s not that simple. There is a lot more to it than meets the eye.....

 PART 2

But it’s not that simple. There is a lot more to it than meets the eye. Cars exclusively use embedded microcontrollers (µContollers) with embedded firmware in preference to microprocessors with loadable software. In order for a microprocessor to function properly in any device, it must contain dedicated internal circuitry and firmware specific to its function, have inputs and outputs and an oscillator circuit among other circuitry and an OS (Operating system). A DVR (Digital Video recorder), or a PVR (personal Video recorder) or a set-top-box or embedded network appliance or data router are just a few examples of such systems. µControllers  are less significant and less sophisticated than microprocessors, more dedicated to its specific need, often cheaper, faster, safer and smaller. Embedded µControllers are therefore the natural choice for car manufacturers. And there are several manufactures that produce µControllers families specifically for the motor trade.

So it should be understood that companies like Bosch, Digifant, Delco  and other engine management ECU manufacturers and electronic module manufacturers uses the same microcontroller chip families or similar microcontroller chip families, designed and manufactured for them by a selected few silicon chip manufacturers.  In the same vein, computer manufacturers like IBM, Dell, Sony, Toshiba and Lenovo, etc. all use microprocessors manufactured by Intel Corporation or AMD in their laptops and computers, whereas Apple uses microprocessors manufactured by Motorola.

Baring in mind, that much like Motorola, Intel Corporation and AMD produces different featured microprocessor chips with different instruction sets,  along with their auxiliary support chips for low-end and high-end computers; such as 4 bit, 8bit, 16bit, 8086 family of chips, 32bit Pentiums, I5, I7, 64bit, XEON, 128bit big Endian and small Endian microprocessors etc; so does Infineon, Altera, Freescale, Atmel and ARM etc, manufacture different featured microcontroller chips for both low-end cars and high-end cars which are specifically chosen for their internal features and software by the various ECU and electronic module manufacturers like  Bosch,  LUCAS, DENSO, Delco, DELPHI, FENIX, HITACHI, HELLA,  MARELLI, Siemens, etc. These microcontroller chip families can roughly be categorized into four sub sectors, those specific to Powertrain functions (P), those specific to the Body and Safety functions (B), those with specific functions for Chassis (C) and those specific to Internal Convenience & communication(U).

In a nutshell all the sub systems in your vehicle are controlled by these on-board computer chips, each at the heart of an electronic module flanked by associated components and sensors. Each of these modules are in fact a fully fledged computer in its own right, situated in various positions throughout the car and linked together by a wired networked called a network bus and all are accessible through the Databus diagnostic interface for adaptation.

When the ignition is switched on, several dashboard warning lamps light-up and stays lit for the duration of the internal test cycle (<30 seconds). Should all tests check OK, all lights goes however if all systems does not check out OK, the relevant light will stay on and a fault will be logged in memory . After the car is started, the ECU monitors all sensors  and continually takes readings from the complete range of powertrain modules and sensors. These readings are then compared with default readings stored in the operational logic of the  system. Should the sensor reading coincide and agree with the stored program value or values, the microcontroller will send the  required outputs to the relevant actuators, for example the injectors. If the sensor readings differ and are out of specification,   "not within the required limits",  it will take another and if this sensor reading continues to be ‘out of limits’ a DTC will be triggered and sent to non-volatile memory. Depending on the nature of the fault, the embedded program may or may not instruct the microcontroller to make internal changes, thus operate on different criteria until a repair is effected, or until the fault has been cleared.

So whenever a mechanical or electronic problem arises in either the Powertrain (P), the Body (B), the Chassis (C) or the internal Conveniences & Communication (U) areas, the relevant module or modules triggers the on-board self diagnostics program and generates a DTC (Diagnostic Trouble Code) which is then stored in the non-volatile memory of the ECU for later retrieval by mechanical technicians. At the point When a DTC code is logged in memory, the system self-diagnosis system also alerts the driver with a visible indication  of trouble by turning on a warning light on the dashboard like the "EPC light", or the "Malfunction Indicator Lamp" (MIL) which on European cars is known as the "Check Engine Light". This doesn't tell you  the nature of the problem, even though it could be something serious, or not. After the necessary repairs are completed, a diagnostic scan tool should be used to clear the DTC errors  and to turn the malfunction indicator light (MIL) or EPC light off. Thereafter the car should be taken on a short test dive to ascertain that the previous drive issue or issues are resolved. Then the car should be hooked up to the diagnostic scan tool once again in order  to confirms that the DTC or DTCs is also no longer present.

The nature of such mechanical problem may  prevent the engine from starting or it may idle erratically, switch off immediately after starting, refuse to rev higher than 1500 rpm and impede driveability (limp mode), difficult cold starting, misfire, lazy acceleration, high idling speed, fluctuating rev counter, excessive fuel consumption, difficult warm starting, excessive black smoke, poor engine response or emits blue/grey smoke,  etc ... Each of these faults and so many others each produce individualized codes.   In most cases it would be expedient to engage the services of a roll-back to get your car to a VW service center so that diagnostics can be run on the car.

With sufficient knowledge and an appropriate diagnostic apparatus (Autoboss, Pico Scope, Range, VCDS, AutoEnginuity,  ScanXLpro), code reader or scanner, plugged into the car's 16 pin diagnostic plug, mechanical minded persons can read these faults, print then or save them to an SD card or harddrive, send signals and communicate with the ECUs, read the measured values and interrogate the actuators. The DTC in memory however do not identify the part that has gone faulty but rather provides you  with a general idea to its area of origin. Often long before a DTC code is generated the fault may already have existed so when the you view the DTC it could show that the fault occurred twice of thrice or even six times before. The ECU software is designed to monitor the frequency of error and if it is an isolated occurrence the ECU clears the fault after a certain distance is traveled but that dependent on the severity of the fault. For arguement's sake lets say 300kms. If it happens once in 300kms it could automatically clears the fault but should it happen four times during the same distance a DTC will be registered, the car could go into limp mode since it may be unsafe to drive the car if it's a breaking or steering issue, or shut the engine off if the O2 sensor went faulty and can't regulate the smoke pollution, or disable starting if the knock sensor triggered the DTC as there may be no oil in sump which could amount to a very expensive engine repair. In the case of the latter, the oil light should have illuminated long before the knock sensor shuts the engine off. However I have encountered a problem with the wires that plug into the oil sensor that became brittle due to engine heat and  subsequently broke off. As a result the sender  sent the low oil condition but it never arrived at the the ECU hence did not turn-on the oil-low light. I only became aware of this when my EPC light went on due to the knock sensor. See picture in blog.   More ...

EPC DEMYSTIFIED

EPC DEMYSTIFIED IN THREE PARTS

PART 1

In a global village where defined lines between languages and nationalities, technologies and terminologies have become completely blurred, it is important to create terms of reference in discussions, so that we are all on the same page but pronunciation can at times offend the ear. To elaborate, some people say "tomarto" (tomato) some say "tomayto", some say micro computer and some say microprocessor, some say Electronic power control (EPC) some say Electronic Pedal control (EPC). But that's just semantics, the bottom line remains, that it establishes a common ground for people of different geographical spaces to discuss common topics.

In response to the hoards of queries I recently received and the abundance of confusion there is out there about EPC (Electronic Power Control); and in reply to the thousands of e-mails I received regarding EPC (Electronic Power Control) that I haven’t been able to reply to as yet nor will ever be able to, I decided to dedicate the next few episodes of my blog to explaining the EPC (Electronic Power Control) problem many VW drivers and VW owners are having with their cars as if they were two year olds. (Not that two year olds can relate the subject at hand).

I have explained EPC in previous blogs, namely EPC light revisited explained and EPC why-engine-light-comes-on, however, I am going to elaborate on the EPC (Electronic Power Control)  concept and demystify it for the benefit of all these people mentioned above and all those destined to encounter this problem at some time or the other. The question is not if you will encounter an EPC problem but rather when you going to encounter an EPC problem, its just a matter of time. Be that as it may, for the sake of simplicity, and by analogy, I'm going to compare the workings of the EPC (Electronic Power Control) in a car to that of a PC (personal Computer) which in my humble opinion will aid understanding.  So here goes....

Electronics as a whole has intrinsically influenced human life globally, especially since the advent of the silicon chip. Through the evolution of said silicon chip, Microprocessors have become so common place, that it finds itself in virtually every modern day technological advancement from computers to televisions, cell phones to cameras, medical equipment to the very cars we drive, to mention but a few. As a result virtually everyone out-there, has heard of, or are familiar with the terms microprocessor, microcomputer or just computer, and as such, it establishes a basis to discuss familiar concepts. Most people in the "Secular World" either owns a computer or uses computers and accordingly have some understanding of its hardware and its software, and how well these complement each other and seamlessly work together. I mentioned this purely in preparation to my assertion that  follows. However, all those non-technical and all-thumbs people and those  who say "you don't have to know how an engine works in order to drive a car", are totally excused.

EPC for Hands-on Dudes, Savvy Ladies and other pragmatic people.
Computers can roughly be subdivided into building blocks, each of which is responsible for a specific function or a collection of functions. As such a combination of these specific functions gives rise to the correct and proper functionality of the computer or computer based device. For instance, the computer hard drive functions as the storage unit that holds the operating system, application programs and user data. The DVD Rom, serial port, keyboard and mouse acts as input devices. Whereas and the speakers, printer & screen act as output devices, doubling-up as the interfaces of information interchange between man and machine (computer). The motherboard houses the CPU (central Processing Unit / Microprocessor chip) it ancillary / auxiliary timing chips, control and data buses, RAM and sub circuitry for  AGP, PCI, MR1, PCMCIA, USB, Ethernet, Fire wire, parallel connectivity, etc. When all these specific components play together nicely, we are guaranteed a fully functional computer and a happy computer user.

Likewise the car can be subdivided into building blocks each responsible for a specific function. In this instance, the engine is the source of propulsion which delivers it to the rest of the drive train. The instrument panel, the steering wheel, the transmission and the braking system constitute some of the input and output devices, also   doubling-up as the interfaces of information interchange between man and machine (car). The electrical system; the ECU (Motronic control unit), Control unit within the dash,  along with its auxiliary modules, oversees the overall timing, sensor, actuator, control and data bus, as well as block components like the Radio, air conditioner and central locking etc. Once again, when all these discrete components play nicely together, we have a perfectly functional car and a happy driver / owner. More...

VAG

VW DIY

In the not so distant pass, whenever something went wrong in your VW, Polo, Jetta, Passat,  Audi, Seat or Skoda,  you could do one of two things. Either  take it to a VW specialist to have it checked out or you could fix it yourself, if you are a hands-on, DIY kind of person. Nowadays the latter option has faded away into obscurity. With the stream of problems VAG cars are having, many of us are in the dark regarding repairs. We make educated guesses, replace parts by substitution, often costing huge amounts of money for repairs and the fault still persists. Below I have out-lined some of the problems I have encountered and with any luck shed some light on the problems you've been having with your VAG car. But before I go any further you may be itching to ask "What is a VAG car?"

Well, VAG stands for Volkswagen-Audi GMBH in Germany, also refers to Volkswagen Aktiengesellschaft or Volkswagen AG for short and Volkswagen-Audi Gelelschaft (Geleslschaft means Association). In essence, it's the same, exact and identical  group. And any car manufactured or sold by them is referred to as a VAG car. Amongst these are, VW, Polo, Jetta, Passat, Audi, Skoda, Touran, Tauareg, Beetle, Tiguan, Golf, Porsche, Amrok,  Rabbit, Bentley, Bugatti, Bora, Phaeton, Vento, Kombi, Transporter,  Lupo and the  Lamborghini, each one with a different engine with varying capacities with obscure three letter abbreviations like, BBX, AAF, AEX and APE amongst many others. However many of them have the same or similar Electronics Bosch Motronic system hardware with software ranging from ME 5.x to ME 7.x, with several support modules in common, networked to the OBD II / OBD2 (On-Board Diagnostic System ver. 2) or Can-Bus (Controller Area Network) standard.

The VW Polo 2007 with new Bluemotion technology can switch its engine off
when it comes to a halt, yet plagued by the legacy VW EPC light problem.

The idea behind this is so that only the  Volkswagen dealership technician are supposed to do the servicing and perform repairs to your car. The VW car manuals specifically discourages anyone other than qualified or trained mechanics /auto-electricians and technicians or mechanicians to perform servicing, especially changing codes and performing readiness test. Under the OBD II and Can-Bus standard, an ECU (Engine Control unit) interfaces with various other modules fitted in the car and controls and manages all sub-circuits. For example, Central Electronics Module, ABS module, Temperature Control Module, Speed-o-cruise Module, etc... When one of these modules detects a fault with one of its components, it registers a error in the non-volatile memory. Lets say you have a front wiper motor problem and it just wont work, but the fuses are OK. Even if you suspect the wiper motor as faulty and it actually is faulty and you replace it, the new wiper motor still wont work after its been replaced and switched on. You first have to clear the error or errors  from non-volatile memory with a diagnostic tool. Then and only then will it work.  

I've had the same results with my power steering which just wouldn't work after some work was done to my car and in the process the Power Steering Motor was disconnected. When it was reconnected the power steering was very stiff and difficult to steer. After going through the entire process of checking and back-tracking it still didn't work. Eventually, when the diagnostic tester was plugged in, two errors codes showed up. The first indicating that the +30V supply had dropped to an unreliable level and the second a power steering error. The first was because the battery was disconnected and the second was because the power steering plug was disconnected. After erasing the two error codes from the non-volatile memory, the power steering work perfectly normal.

I can assuredly say that I am not alone or rather that my car trouble is not unique, neither am I the only VW owner having car trouble (see previous blogs).  It appears that my 2007 Polo Classic Highline shares most of the problems listed below with my fellow VW owners. There are probably hundreds if not thousands of other  VAG car owners experiencing the same issues with their cars as I am experiencing with mine. Here are just a few of the problems that my fellow VW owners shared with me :-

"VW polo dashboard brake light stays on" / "EPC instrument fault indication light is on" / "VW polo warning lights on dashboard" / "VW  polo classic is showing epc light, starting and dying" / "polo dashboard controls" /  "VW  polo warning lights off power steering" / "warning light on dashboard" / 2007 volkswagen polo problems" / "audi electronic power control indicator" / "won't rev" / "VW Polo EPC Warning Light" / "golf mk4 dashboard warning lights" / "epc instrument fault indication" / "VW  door key problem" / "VW  polo accelerator position sensor (g79)" VW throttle body sensors"

NB! Fellow VW drivers found this site to be helpful and was interested in checking out the following sites as well.

expowp, photojani, controversy365, nerdytoys, lovelifelovehealth, sightsofcapetown, sowpbox, electroniques, blogspot-at, photo-magix, godssites, glycomix, arth-ritis, forex-bid, foodsofthecape, languagesbarrier, pimpyocar, e-gimos.

Should you find this blog informative or even help full in the very least, please recommend it to others and click on the g+ tag below. Thanks.

VW ELECTRONIC POWER

EPC LIGHT EXPLAINED

As I mentioned before in my older blogs, the new generation of VW cars are designed to turn on an EPC Light (not check engine light) so that only the  Volkswagen dealership service technician or technicians are supposed to do any an all servicing and repairs.  The VW workshop manuals specifically discourages anyone other than a qualified or trained mechanics / auto-electrician and automotive technician to perform servicing, especially changing codes and performing readiness test.  This is because  incorrectly set readiness and adaptation settings can completely disable your car and virtually render it useless. To repair it would then cost a small fortune.

CHECK ENGINE LIGHT

An earlier blog, covers some late model VAG cars with fuel injection and electronically controlled throttle body instead of the traditional accelerator cable controlling the throttle valve. It is called Drive-by-wire or DBW for short. When the Engine Control Unit -ECU, which invariable is a computer in its own right detects a fault  Diagnostic Trouble Code - DTC  in the Drive-by-wire system, it registers a fault Diagnostic Trouble Code - DTC in its non volatile memory and turns on the EPC light, disables the accelerator and throttle body, limit the engine to a maximum of 1500 rpm -"Limp Mode".  This would be sufficient power to "Limp Mode" the car to a service centre without causing further damage to the car or unduly polluting the air should the fault cause it to smoke. This is a safety precaution and can be equated with, what would happen if  an accelerator cable got stuck in the downward position. Disaster could follow. The Engine Control Unit -ECU collects faults Diagnostic Trouble Code - DTC from all senders and stores an internal list, which is only visible with a diagnostic tester. Diagnostic Trouble Code - DTC can range from excessive emissions to - intermittent air bag connections, from brake light failure to - depleted brake pads, from interior ultrasonic failure to - immobilizer problems to even disconnecting the battery. Each of these faults generates codes, some of which can be viewed in future blogs.

Should the Volkswagen Engine Control Unit -ECU  considered a Diagnostic Trouble Code - DTC to be so serious that it could possibly do harm to the engine or the environment, it will inhibit the throttle function and limit the engine revs or even disable starting or idling completely.  Unfortunately the only way to repair such problems, is to connect the  Volkswagen Golf,  Jetta, VW Polo, or Volkswagen Beetle, to a dignostic tester through its CAN-Bus / OBD2 / OBDII port and view  Diagnostic Trouble Code - DTC  if any and  Diagnostic Trouble Codes, clear them from memory and perform corrective procedures.  Below is an overview of the Electronic Power Control Circuit - EPC and how the Drive-by-wire system operates.

The basic operation of  the Electronic Power Control (EPC) Schematic showing inputs
from drive-train sensors and output signals to drive-train actuators.

Other INput senders could result in similar problems. For example - the Oxygen Sensor could detect that the exhaust fumes carbon mixture exceeds the prescribed level which is toxic to  the atmosphere and the environment. It could disable driving of the vehicle by enabling the Electronic Power Control Circuit - (EPC), turning on the EPC warning light or even disable starting not allowing the car to idle. This could be due to a dead plug causing the idling to be erratic and not burning up all the fuel. This un-burnt fuel will invariably change the exhaust fumes composition which triggered the Catalytic Converter and Oxygen Sensor in the first place.

Like wise, when the brake light bulbs blow or the fuse to the brake circuit blows, an INput signal from the brake light sender could also activate the Electronic Power Control Circuit - (EPC), turning on the EPC warning light causing the car to go into "Limp Mode" because driving a car on a public road without brake lights is an accident just waiting to happen. In fact the Engine Control Unit (ECU) looks upon this car as non-roadworthy as a safety procedure. In a previous blog I described an Electronic Power Control Circuit - (EPC), which switches on the EPC light problem caused by an INput  signal from one of the knock sensors with the same results as above. Other senders INputs that can cause similar problems are:-

The Engine Speed Sender G28 situated at the flywheel.
The Hall Sender G40 situated at camshaft pulley
The Hot Air Mass Meter G70 and intake Air Temperature sender G42 situated near intake manifold.
The Lambda probe G130 situated upstream of catalytic converter
The Lambda probe G39  before catalyst converter
The Knock sensor I - G61 below intake manifold
The Knock sensor II - G66 below intake manifold
The Accelerator Position Senders G79 and G185 embedded in accelerator pedal (EPC Problem)
The Clutch pedal switch F36 situated in the drivers foot well.
The Brake light switch F and brake light switch F47 situated in the drivers foot well.
The Throttle control valve / motor drive assembly  J338 
The Angle Senders  G187 and G188 situated inside throttle body.
The Fuel Pressure Sender -G247

NB! VAG car owners who found this site to be helpful 

were interested in the following sites as well.

expowp, epc warning light, service engine light, photojani, service engine light on, service engine light on,  controversy365, check engine light service, epc car light, epc in car, nerdytoys, epc light on car, what is epc on a car,  lovelifelovehealth, check engine codes, check engine light codes, sightsofcapetown, what does epc mean, what does epc mean in a car,  sowpbox, what does epc mean on a car, check engine light,  electroniques, check engine light flashing, check engine light on,  blogspot-at, blinking check engine light, flashing check engine light,  photo-magix, service engine soon, service engine soon light,  godssites,  what does check engine light mean,  glycomix,  arth-ritis,  forex-bid,  foodsofthecape, engine warning light, languagesbarrier,   yellow engine light,  pimpyocar, what does the check engine light mean,  e-gimos.

MAKE REAL MONEY ONLINE WITH FOREX

MANIFOLD

MANIFOLD / EXHAUST

It was about 2:30 a.m. when I returned from a long distance trip. I was tired but smiled to myself before I climbed into bed because my 2007 VW Polo Classic Highline really performed well and brought me home without incident. I was amazed, blown away in fact. 

After breakfast the following morning, I intended to go to Milnerton to see a client but when I started the VW Polo, I was greeted by  frighteningly loud noise. I smiled too soon. Immediately I switched off the engine. It actually sounded like the VW Polo had no manifold system fitted at all. For the record it wasn't like the sound of a broken silencer or a hole in the exhaust system. It literally sounded as if there wasn't any exhaust system at all.

My first thought was that someone must have liberated my exhaust system during the night whist I was asleep and sold it off as scrap metal. Theft in my locality has become quite rife and this is known to have happened. Radiators and batteries seem to be targeted more often.  However, on closer inspection I was relieved that the exhaust was still there. I started the VW Polo once more rolled underneath the front suspension and discovered hot air was blowing from a space  where the flange gasket is located. It was very awkward to get my hand in there and I was wondering what this repair was going to cost. A trip to "Mister Silencer" and three hundred and twenty bucks later the VW Polo was once again ready for the road. I expected one of the dashboard EPC warning lights to light-up or one of the CanBus interconnected computer modules to immobilize the car but its seems that the manifold exhaust  just runs much too hot to attach a sensor to it.

Anyway, in order to fix or fit a new flange gasket the complete knuckle had to be removed. They hoisted the car on a maintenance lift and inspected its underside for the origin of the noise. It came from above the flexible bend which looked like matted wire mesh. Essentially the joint between the manifold branch and the exhaust manifold had to be removed.  I was told the flexible mesh compensate for vibration, should the silencer knock against a pavement of something, it wouldn't brake off of get damaged because of its flexibility.

Just two days prior to this, a young women ran into my rear bumper with her sparkling new look Audi A8 whilst she was chatting on her cellphone. There was no physical damage to neither of the cars but thought that she was the cause that my exhaust had given trouble. According to the dude at "Mister Silencer", its highly unlikely because the impact from behind would not have pushed the exhaust towards the engine because of its flexibility. Oh well,  either way I had to pay for it. FYI my VW Polo had every service on time since new and currently has 88250 Km on the clock. Soon it will be going for its 90000 km service and my timing belt will be changed. I've been driving with the dreaded fear that it might snap in mid travel and bend all my valves in the process or even bust the tops of one or two pistons.

In my first blog I mentioned I simply love German engineering because when a German designed car snaps a timing belt, there is no mechanical damage to the engine. This is so unlike the Japanese, American, English and French designed cars, all of which bend valves, bend conrods, break pistons or knock holes through their cylinder block. Since my VW Polo Classic 2.0L Highline is soooo different from all the previous German cars I owned, I just have this feeling it was designed along the same money making monopolistic ideology of modern car design - the cash cow that  sells spare parts.

Dudes and Dudettes, if you found this blog informative or even remotely helpful, recommend it to others by clicking on g+1 below.