EPC issues

EPC Issues

EPC complaints have become the most common Volkswagen fault and outstrips check-engine-light three to one. It is one of the most tiresome and frustrating  faults to diagnose and repair because the only way of knowing that your most recent repair cured your EPC problem, is when it does't occur in the same situation under the same conditions thereafter. Mechanisms generally refer to Electronic Power Control (EPC) faults as evil, a waste of time and the cause of embarrassment.

Many disillusioned VW car owners can confirm that they've taken their vehicle to at least 2 different workshops to fix their respective EPC light problem. Often wanting a refund from the first workshop as they didn't fix the EPC issue, but only said they did. It's also known fact that tons of spare parts suspected of causing EPC have been replaced that didn't need replacing in the first place. Trial and error EPC repair seems to be the order of the day among motor mechanics. Even the agents are guilty of this and VW car owners are generally fed-up of mechanical and electronic competence. Many car owners and DIY mechanics are longing for the days when cars had a lot less electronics, were easier to diagnose and repair and one didn't need a degree in automotive engineering to replace something as meager as a MAF sensor. The word EPC among many others, is just one of the mechanical jargon that has come to invade the car industry. There are so many; to list just a few. Several of them capable of throwing an EPC light.

AIR: Air Injection System
ACC: Adaptive Cruise Control
ABS: Antilock Braking System
AWD: All-Wheel Drive
BHP: Brake Horsepower
CEL: Check Engine Light
CO2: Carbon Dioxide
CKP: Crankshaft Position Sensor
DLC: Data Link Connector
DDI: Direct Diesel Injection
DPF: Diesel Particulate Filter
DRL: Daytime Running Lights
DTC: Diagnostic Trouble Codes 
DSG: Direct-Shift Gearbox
ECT: Engine Coolant Temperature
ECU: Electronic Control Unit
EGR: Exhaust Gas Recirculation
EPA: Environmental Protection Agency
ESC: Electronic Stability Control
ESP: Electronic Stability Program 
FSH: Full Service History
FWD: Front Wheel Drive
IAT: Intake Air Temperature
KPH: Kilometres Per Hour
LED: Light Emitting Diode
LSD: Limited Slip Differential
LPG: Liquid Petroleum Gas
LWB: Long Wheelbase
MAF : Mass Air Flow (sensor) 
MAP: Manifold Absolute Pressure
MIL: Malfunction Indicator Light
MPV: Multi-Purpose Vehicle 
OBD: On-board Diagnostics
PCM: Powertrain Control Module
RPM: Revolutions Per Minute
RWD: Rear Wheel Drive
SUV: Sport Utility Vehicle
TDC: Top Dead Center
TCS: Traction Control System
TCU: Transmission Control Unit
TPS: Throttle Position Sensor
VCM: Vehicle Communications Module 
VIN: Vehicle Identification Number
VRM: Vehicle Registration Mark
WOT: Wide Open Throttle

The letters EPC in the automotive sector initially meant Electronic Parts Catalogue. Recording every conceivable component used in the  manufacture of that car, listed in alphanumeric order. Some EPC are exclusively online versions, or downloadable as pdf. Some cover specific cars  and others cover several makes of cars and is normally free, whereas the more elaborate EPCs with specialist automotive service data is charged for per search or as a monthly subscription.

For example, the ETK 2018 EPC  is specific to BMW,  Rolls Royce, Mini and the Chinese Zinoro which is the luxury automobile brand owned by BMW Brilliance specializing  in electric vehicles. ETK comes at an exorbitant price, in either downloadable or CD/DVD form. The Volkswagen  ETKA online /  ELSAWIN EPC is specific to Volkswagen, Audi, Seat and Skoda and spans 6 CDs and is also fairly expensive. It is an encyclopediac like compendium covering VW, Audi, Seat and Skoda vehicles manufactured between 1947 and 2018 in varying degrees of detail. 

It also includes the actual service & repair software used by factory technicians at Volkswagen, Audi, Seat, Skoda and their dealer workshops throughout the world. As such it would be in indispensable resource for the Volkswagen enthusiast but is also overkill for most. However most modern day cars have an EPC circuit which essentially deals with the torque of the vehicle. Using one of these catalogues and its diagnostic diagrams to identify these components and problems is one of the easiest ways of fixing EPC problems. To fix your EPC problem, click here, here or here.

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EPC light came on and can't start the engine,  / EPC warning symbol came on today while driving, / VW Polo EPC  Warning Light came on and lost power.  / Can I drive with EPC light on? / VW Polo no Throttle and EPC light on, / What causes the EPC light to come on? / What does EPC mean on the dashboard? / What is an EPC light?  / What is limp mode,  / What is limp-mode home?, / What is the VW EPC Warning Light, / What is EPC on a Volkswagen? / What does the EPC light mean on a VW, / What does the EPC Warning Light on my dashboard mean, / What does it mean if the EPC warning light comes on in a Volkswagen, / How to Fix EPC Light on a VW,  / What is an EPC light on Volkswagen?, / What Is the VW EPC Warning Light? / What does it mean if the EPC warning light comes on in a Volkswagen?  / What does an EPC light on the dash of a Polo car mean?

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. 

My EPC light came on

My epc light came on

Virtually every  motoring enthusiasts who owns a Volkswagen Golf TDI  simply loves its torque; its drive, its racy performance, its braking, its fuel economy and especially its manual transmission model. Be that as it may, 6 out of 10 Volkswagen and Audi owners are unhappy about Volkswagen as a whole. Unhappy about their cheating devices, unhappy about the emission scandal, unhappy about the entire VW TDI buy back claims processes, but more specifically unhappy about having to give back the car that they love so much.

According to the 225-page court document that outlines VW’s settlement, which reads,

“At the present time, there are no practical engineering solutions that would, without negative impact to vehicle functions and unacceptable delay, bring the 2.0 Liter Subject Vehicles into compliance with the exhaust emission standards.” 

This is so wrong on so many different levels hence most VW and Audi owners are completely pissed-off -pissed-off at Volkswagen. Event hough most VW TDI enthusiasts haven't returned their cars, they are already missing them, even before it's taken back; all of them very unhappy about it. It's always good to be optimistic about the buyback outcome but pessimistically speaking, VW, Audi, Seat and Skoda owner's are all complaining about their cars, ranging from, 

"My epc light came on and I lost power",  to 

"I got stranded on the side of the highway today for  almost an hour when my EPC light went on",  to 

"The first time it happened, the EPC light turned on and loss of  power lasted for a day and then it went away on it's own",  This is now the third time this happened, the EPC light comes on and then my car just loses power", 

"I took my car to the VW agents for a EPC problem who then said they  found a few error code but they didn't know what was wrong, so they just reset them",  

"Totally disgusted, by the dealer's complete and utter  disregard to accept responsibility for their pathetic  workmanship. They threw a dozen parts at the problem at my cost and the EPC problem is still not solved", 

I've kept track of all the faults on my VW Polo, and it fills a foolscap page.  It ranges  from interior parts falling off, the foot rest lodging itself under the brake pedal whilst driving, the brakes randomly engaging and causing under steer, to continual  creaks from the suspension, the gearbox is crap, not to mention my daily battle with an EPC issue. My Polo's been back to VW a full 58 days during this  year, yet they still haven't fixed all the issues and  as a result I very nearly caused 2 accidents due to  the on-going braking issue, and the EPC going  into limp mode on an on-ramp,  

I've spent more than a  year trying to solve  the problem “EPC” light problem, I've already  replaced  the Acceleration pedal, Two sensors located  under the engine, Cambelt kit, Throttle Body, all the  injectors and the ignition coils and the ECU,   but the light still regularly comes on,  

The VW guaranteed future Value a Rip-Off! I have never  been so dissatisfied with help from customer service and  will NEVER EVER purchase another Volkswagen nor recommend it to anyone I know, because of the shoddy  way we were treated. The staff working in VW credit and financial are rude and disorganized, no wonder they losing all their customers.They charged me for items covered by the warranty.

And the list goes on. These are only a few of the nice clients  I wouldn't want to repeat what some of the other "not so nice" clients said about Volkswagen and their cars, especially about the EPC light and limp mode. Electronic power Control (EPC) has become part of every VW, Audi, Skoda and Seat owners vocabulary, yet few understand what it really is. So allow me to put you in the picture.

Electronic Power Control

The EPC warning light is just a regular warning indicator light, much like your handbrake light or your oil indicator light.  The handbrake light just tells you that the hand break is engaged, alternatively that it hasn't been released. Likewise the oil light is a warning indicator that alerts the driver to the fact that the oil is low. In the very same vain the EPC warning  light is just an indication that something awry has happened in your Volkswagen's torque system, which is a sub-circuit of the Electronic Power Control Circuit.  

So what exactly is the torque system ? you may ask. Well is consists of various interlinked components, where the functionality of one is subject to another. These components are your  Volkswagen's entire drive-by-wire system, incorporating the  accelerator pedal, the throttle body, the cruise control, the traction control, the breaking system, the fuel pressure system, the knock sensors and the ECU, along with the wiring harnesses that inter-connects all these components. The wiring harness is a safer substitute for accellerator cable in all drive-by-wire systems.  

The accelerator pedal

The accelerator pedal for that matter, has 2 independent potentiometers inside a module that's permanently bonded to the pedal itself. These 2 potentiometers are call senders by Volkswagen and known as G79 and G185, but I will use these terms interchangeably.  This module is connected to the ECU via a 6 wire harness, essentially 3 wires per senders. Before, I continue, let me tell you what a potentiometer is, if you not familiar with the term. Another name for a potentiometer is variable resistor or a rheostat. It is most commonly used as rotary the control knob on a radio, with which to control the level of its volume. It is also commonly used in  the bedroom light dimmer to adjust the level of light needed. 

Each sender has 3 pins, 1 for each end of its resistor and 1 pin for its wiper. All three pins of each sender are connected to 3 pins specific pins of the ECU. The ECU sends each sender a high and a low voltage across their resistors and receives a difference fed back voltage from each sender's wiper. The 2 wiper feedback voltages are referenced and inverted to one another and translated by the ECU as how much the accelerator pedal is depressed.  Should  the ECU loose either of the wiper inputs for even a fraction of a second, the ECU limp mode program will execute, the EPC light will come on and the engine wont rev higher that 2000 rpm any longer. When my EPC light came on, I traced it back to a fault/ intermittent accelerator pedal due to error codes P1630  to P1634 and P1639.

The throttle body

Much like the accelerator module, the throttle body also has 2 integrated potentiometers called angle sensors known as G186 and G187. They inform the ECU how wide open or closed its butterfly is. The throttle body also has a built-in stepper motor known as an actuator. The ECU essentially translates the accelerator pedal position to a voltage / pulse train that drives the stepper motor, that in turn opens and closes the throttle body butterfly, controlling  air flow between air filter and intake manifold.  In a nutshell, a remote control system that mimics the operation of an accelerator cable. If for any reason the throttle body is removed or dismantled, it would be necessary to perform the adaptation procedure. When my EPC light came on, I traced it back to a  throttle body problem with error codes P1171 - Angle Sensor 2 for Throttle Actuator (G188) Implausible Signal.

The cruise control

When the cruise control is enabled, a signal is sent to the ECU to this effect, which in turn sends the necessary voltage / pulse train to the throttle body stepper motor to keep it steady and received feedback from G186 and G187 to further control the process., ignoring the accelerator pedal until the brake is applied or receiving a signal change from the accelerator pedal. Should something go awry in this process, cruise control will be canceled, the ECU limp mode program will execute, the EPC light will come on and the engine wont rev higher that 2000 rpm any longer. When my EPC light came on, I traced it back to a  cruise control switch problem with error codes  00895 - Cruise Control Switch (E45) Defective.

What is Limp Mode

What is Limp Mode

Limp mode is a safety feature specifically designed into the OBDII system to protect the engine and or transmission from damage. In the event of a engine malfunction or in response to the "warning" lights,  the driver would be provided with advanced warning giving him or her sufficient time to get the car off the road. 

This safety feature is triggered when an abnormality is detected with the logic circuitry by the vehicle's computer, viz  Engine Control Unit (ECU) aka Electronic Cobtrol Module (ECM) or even the Transmission Control Module (TCM). Theoretically these modules receive constant signals from the MAF, MAP, TPS, vehicle speed sensor, cam position sensors, engine sensor and so many other sensors. As long as these signals that stay within the “normal” range of predetermined signal levels, all's well. Since operating conditions do change as the vehicle is driven, these signals will somewhat change and may occasionally exceed or drop below the pre-programmed level.

This event alerts the ECU/ECM to the glitch and gets stored as information. This glitch condition is them monitored by the ECU/ECM for the next few driving cycles. A driving cycle is any distance traveled between the start of the engine and swtching the engine off. It this glitch occurs a few more times during sucessive driving cycles it is registered as an error code in the ECU/ECM's non volitile memory. However if the glitch doesn't reoccure during sucessive driving cycles, that glitch is deleted.

Sometimes the yellow check engine would turn on, though the car drives and performs perfectly normal. After a few cycles the yellow check engine light then turns off as if the event never occurred.  Sometimes the glitch like  a misfire occurs and could be severe enough the trigger Limp Home Mode. Limp home mode is an operating condition that is triggered by the vehicle ECU. In the case of an automatic vehicle, limp mode will limit the transmission to 2nd gear and limiting the speed to 15 to 20kms p/hour. This may cause the engine to have a higher rev than you may be accustomed to hearing. This will also cause the vehicle to be sluggish on pill away since it is limited to 2nd gear and will not change.

Once the problem / error code is diagnosed and the appropriate sensor that's causing the problem is seen to or replaced, everything should be back to normal.

Fail Safe Mode

Fail Safe Mode

"Fail Safe Mode" aka "Limp Mode"  is becoming more common as the guarantees on cars of all makes and models are starting to expire. As cars are getting older, they also tend to be affected by fail safe more frequent than ever before. In fact now a days, its quite difficult to find a car fitted with OBDII that hasn't gone into "fail safe mode" or "limp mode" at some time or the other,

"Limp mode" is normally instantly identifiable and have a number of symptoms. These symptoms range from the car's engine switching off in mid travel, the engine idling but its won't rev, the car performing sluggish on take off, or in automatic models, the transmission doesn't seem to want to shift. These are often accompanied by a flashing or permanently on check engine light or transmission light and the EPC light. When this happens to you, its best to get your car to the side of the road and out of harms way as quickly as possible. I've experience limp mode several times with my VW Polo 9N and one of them stands out as a near death experience when I just about managed to limp my car away an fast on coming pantechnicon truck, before it could hit me. 

Since VW is known to have cheated on VW vehicle test, namely the during diesel scandal, there's an idea that's been making its rounds on social media, claiming that "limp mode" was engineered by Volkswagen AG as a way of making money from all VW owners when their vehicles start to misbehave. However, this is a myth or rather it's not exactly true because "limp mode"  doesn't just affect Volkswagen manufactured cars but seems to be more prevalent on Honda,Toyota, Dodge and Chrysler vehicles with a computer controlled transmission, though not specifically.

Transmission Limp Mode

Automatic Transmission are plagued by both electrical and mechanical issues because  the  Transmission Control Module  (TCM) controls the process of shifting gear;  and because it's  located inside the rear end of the transmission itself, constantly subjected to extreme heat from the transmission oil. As such, the ribbon cable inside the becomes hard and brittle and sheds their PVC covering causing connections to short circuit or cause sensors to malfunction.

Both the Transmission Control Module (TCM) and the  Engine Control Module (ECM) depend on a stable 12 volts supply  to operate properly. So by implication, a faulty alternator can give rise to a low batteries or even dirty battery cables can cause  intermittent power issues, causing these modules not to function optimally, resulting in "Limp Mode".

When faced with a "Transmission Limp Mode" it is worth trying to perform an Adaptive learning Procedure before limping it to the service agents. This will hopefully reset the TCM and eradicate the problem. So turn on the ignition to the position where all the dashboard light are lit. But don't start the engine. Then depress the accelerator pedal all the way in, and keep it there for 1 minute and while keeping the pedal depressed turn the ignition off. Release the accelerator pedal and wait for another minute then start the car. 

Russian Autotech

Russian Autotech

Greetings fellow Volkswagen owners. I'm certain most of you will agree with me that as huge as the Internet is, it's often hard or rather difficult to find exactly what you looking for. More often than not, this pertains to information  on automobiles of every kind but especially VW, Audi, SEAT and Skoda vehicles. Be this as it may, it certainly doesn't mean that these sought after help files or information even exist; though several "mechanical services web sites" allege that they have all the answers to you motoring problems, offering said information on a paid subscription basis. In reality, there is absolutely no guarantee that they actually have the answers you need to fix your Volkswagen,  Audi,  Skoda or SEAT. The worst would be after subscribing, that this is in fact the case. 



To make matters worse, since the diesel-gate scandal, Volkswagen AG hasn't been forthcoming with information needed by the general public in order to fix or maintain their Volkswagen, Audi, SEAT and Skoda vehicles. They've been far too busy dealing with the fallout of the "diesel dupe". In the US alone, Volkswagen has already paid over €25 billion in fines and litigation costs. Regardless of this, the Dieselgate scandal doesn't look like it's going to abate anytime soon. 

Notwithstanding, this hasn't deterred Volkswagen from extending a €1.75 billion deal with Russia's GAZ group until the year 2025, to produce VW, Audi and Skoda brand vehicles at their Gorky plant in Nizhny Novgorod Oblast, despite the collapse of the Russian ruble. Meanwhile the Kaluga plant in Russia continues to produce VW Tiguan, VW Polo and Skoda Rapid models, as well as build 1.6L gasoline engines. Russia has long been touted to become the largest single car market in Europe, eclipsing Germany’s 3.35 million new vehicles registered last year though currently, many Russians can't afford to buy new cars. 

The most significant thing about this operation, is that several thousands of  Russians were empowered by VW and Audi and privy to their technology, to the point that they are willing to share it with whoever is willing to ask. So, all you peeps  who are having trouble with your VW's, Audi's, Skoda's and SEAT's and seek repair information, there are several Russian Websites that have hoards of free VW, Audi, SEAT and Skoda information that is not normally available on English / American websites. Below are a few links to Russian Websites that may have the information you are looking for. The images in this post are screen shots from these websites. Best of luck with your repairs.

The first site is  http://vwts.ru/  .... this is a Volkswagen Technical Site. All information is in Russian. Login to http://vwts.ru with your facebook account. If your Russian, like mine, extends to yes and no - "да (da) and (нет) net" respectively, then its best  to download  Google chrome's translation extension in order to make sense of the documentation. Some of the documents are in PDF format, mostly in  Russian and German but I've downloaded several written in English. This site also has a forum vwts.ru/forum/  but it appears to be insecure.

http://volkswagen-org.ru/ ... this site covers Golf 1 - Golf VI, Volkswagen Polo, VW jetta, VW Passat, VW Phaeton, VW Tiguan, VW Touran etc. It seems that its administrator has locked down new registrations, but if you manage to login, do so with the facebook icon.

https://www.vw-bus.ru .... this is a forum covering the VW combi T1 - T5, the LT, crafter, the VW Caddy and the Amarok, with members living in Russia, Belarus, Ukraine, Kazakstan, Baltic States and Europe.

https://www.drive2.ru/   ... this is a site of general interest but has good coverage of VW, Audi, Skoda and SEAT.

Hall Sensors

VW POLO

Volkswagen has always had an upstanding reputation (other than for the emission scandal) for manufacturing quality vehicles at affordable prices. One such car is the VW Polo hatchback which has also become one of the most popular cars in South Africa, and it’s really not hard to see why. The VW Polo is a compact car, but when driving it, it somehow feels larger, somewhat like its bigger brother - VW Golf. Should you buy one, you would certainly agree that the VW Polo has universal design appeal, that it has good performance, decent fuel economy and is sold at a relatively affordable price. 

Hall Sensor Hall Effect Sensor Switches A3144 / 3144E / OH3144E
in a TO-92UA 3 pin SIP package can be bought for as little as 1 USD

Volkswagen has capitalize on this winning formula for years and has given us plethora of Polo's to choose from ranging from the Polo Trendline, to the Polo Comfortline, to the Polo Highline, not forgetting the Polo Cross and Polo GTI which comes in 3 and 5 doors classic and hatchback versions. Engine capacities and engine technologies range from 1.2 TSI 66kW and 1.4 TDI 55 kW for the Trendline,   1.4 TDI 77 kW, 1.2 TSI 81kW for the Highline  and 1.2 TSI 81kW Highline DSG, to  1.0 TSI 70 kW BlueMotion. The sedan or VW Polo Classic comes in  1.4 & 1.6 trendline, 1.6 comfortline / tiptronic, 1.9 tdi highline (74kw)  and 2.0 highline (85kW).  There is even a GTI (Grand Touring Injection), a FSI (Fuel Stratified Injection), TSI (Turbo Stratified Injection) and a TDI (Turbocharged Direct Injection), to choose from. 

Clearly there's a Polo out there waiting for you! Having said that, owning a Volkswagen doesn't come without challenges, personally I think the biggest challenge is more likely than not the dreaded EPC light that triggers at the most inopportune times. The EPC circuit has several sensors that feeds into the ECU among them Hall sensors. From my experience hall sensors tend not to like heat, even though their specification sheets rates them above the requisite heat range.  

This datasheet gives you a good idea of a hall sensor's specifications 

Hall sensors are pervasive throughout modern day cars. Hall sensor, aka Magnetic sensors essentially converts magnetic pulses into electrical input signals for processing by electronic circuits. Magnetic sensors are solid state devices meaning there are no mechanical moving parts inside, its all electronics taking place in a sealed chip of silicon, making them immune to vibration, dust and water. This makes them popular choice by electronics designer engineers for several types of application ranging from  distance sensing, to velocity sensing, to position sensing, to  speed sensing, to directional movement sensing etc.

Hall sensors are used for angular position sensing of the crankshaft to determine the firing angle of the spark plugs. They are used for magnetic position sensing in EGR systems. They are used for wheel speed detection for the anti-lock braking system - (ABS) and speedometer. Throttle bodies with DC motors use hall sensors for position sensing. Hall sensors are also used to determine the position of the car seats and locking of seat belts. Hall sensors are employed in automatic transmissions as magnetic neutral position switch, as actuator sensors, as speed and direction sensors, for gear detection and clutch position sensing. Hall sensors are used as engine speed sensor and also as the vehicle speed sensors.  And the list goes on.

The following images depicts a hall sensor replacement inside the distributor of and Audi 5-cylinder engines 2.0 - 2.3. As can be seen the the wires have distinct colours , the red wire is +5V / 12V supply, the black wire is negative / ground and the yellow wire is the output of the hall sensor / sender.

There is space under the black plastic holder where the wires connect to the hall sensor.

Multi purpose hall sensor for automotive use, but the military spec hall sensor is a better option

The sensor is replaced, solder joints covered with fiber glass sleeving then epoxied into place.

Hall sensor plate reassembled

Hall sensor assembly fitted into distributor housing

As I mentioned in a previous blog, Hall sensors don't like heat and tend to malfunction when they get too hot. My first experience with hall sensors were when I was working as an electronics engineer for A Television and Video repair company. A video machines that employed a hall sensor in its take up clutch stopped working due to overheating.  By squirting the hall sensor with a blast of servisol rapid cooling spray, it started working again. I repeated this exercise a few times to make certain that the hall sensor was the culprit, after replacing it, the machine worked just fine. 

Then I also had a problem with my Opel Kadett 1.8 GSI  when driving in peak hour traffic. It would switched off and refused to start.  But after allowing the engine to cool, it started just fine and would be perfectly ok for days until I got stuck in bumper to bumper peak hour traffic again. The dealer had a field day with my car, telling me that they repaired a bad earth under the dash board, only to find out in peak hour traffic that they misdiagnosed. Then I was told that the loom was replaced, then I was told the ECU was replaced and finally that a hall sensor inside the distributor was replaced. This fix the problem once and for all. The images above is for the same symptoms on a Audi  2.0L 5 cylinder.  As perfect as hall sensors are for most applications, where there is excessive heat, they will misbehave.  Perhaps hall sensors mounted in heat intensive spots like the engine speed sensor, should be designed with a heatsink or have its own cooling fan. This advice is as relevant for current model cars as it was for the Audi 2.0L 5 cylinder.

Volkswagen Polo

Volkswagen Polo

The Volkswagen Polo Vivo is undoubtedlty the most popular, as well as the  best-selling car is South Africa. Looking at the top ten vehicles sold in South Africa, VW Polo Vivo takes first place, the Volkswagen Polo takes third place and the Vw Golf takes tenth place. Looking at the frequency of problems encountered with Volkswagen vehicles  in general, it appears that the VW Polo 2002-2009 models are far more reliable than the VW Polo 2010—2016 models. These models are prone to EPC problems and several Polo owners have complained that they encountered EPC problem with their cars with as little as 700km on their clocks.

The most troublesome generation 5, VW Polo seem to be the 2011 model, but the 2012 model takes the cake for the annoying knocking sounds coming from the suspension when going over speed bumps and pot holes.  But this knocking sound isn't unique to the Polo 2011 and 2012 models, it also affects the Golf Mark 7, the Volkswagen Transporter T5 and Polo GTI, etc.

It seems that somehow the strut mount bolts in the engine bay of these Volkswagens haven't been torqued properly. The rattling and knocking noise coming from the shocks occurs when driving over pot holes  or over speed humps, especially when the shock is fully extended or when driving slow.  In some cases the noise comes from coil-over assembly. These coil-overs squeek and creak at random and sometimes the rear ones squeak worse than the front ones. We found by removing the damper adjustment knob and tightening the 17 mm nut in the middle of your strut top,  and   holding the centre with a 7 mm allen key,  the noise is  somewhat reduced but is very disconcerting since these models are relatively new cars. 

Its probably best to re-torque these nut between 45-60 ft/lbs with a correctly  calibrated torque wrench. In my opinion there should have been a total recall on VW Polo 2010—2016 models for this problem. 

Loss of Power

LOSS OF POWER

On Sunday past, whilst taking my family for a drive along our scenic coastline on the Western Cape, I happened to see no less than three Volkswagen cars, each being loaded onto a roll-back. A VW Polo Vivo in Muizenberg, an Audi S4 in  Fish Hoek and a VW Scirocco in Scarborough. I couldn't help but feel awkward about my own Volkswagen Polo because after all, three out of three vehicles on the roll-backs were Volkswagen manufactured cars. I would have felt loads better if at least one of them were a Toyota or a Ford or a Honda. Understandable there are a lot more Volkswagen vehicles on the road than any other make, hence the higher failure rate.  

However, I instinctively pulled over for a chat with the driver of the Scirocco to inquire about the problem. It's owner Gwendaline. apparently parked her car to go for a walk on the beach and when she returned, had difficulty in starting her car. When it finally started , the whole car shook like her washing machine does in its spins cycle.  According to her, the Scirocco  is  really an excellent car with very few issues other than regular EPC light issues; and that its 18 inches tyres are a bit expensive. So we started talking about the EPC - Electronic Power Control and she seems really knowlegeable about it.  Our conversation went something like this.

Electronic Power Control

The EPC warning light, is just an indicator light powered by the Electronic Power Control circuit. Most people are under the impression that it indicates that there is something wrong with the engine when it light up. But this is not exactly the case, because the EPC light does come on when a brake light is fused or the fuel tank cap isn't properly closed.  When The EPC warning light flashes or stays on, it merely alerts the driver to a problem that may exists in your Volkswagen's throttle system. The throttle system encompasses  the throttle body, the throttle control motor, the accelerator pedal, the drive-by-wire electronics, the traction control, the cruise control, the stability control, the fuel delivery system and even the braking system and all their sensors, etc.. 

What does it mean when the EPC warning light turns on in a Volkswagen?

The throttle body motor opens and closes the butterfly valve located on the intake manifold which regulates the amount of air that goes into the engine, in relation to the position of the accelerator pedal. Implying the higher the air flow into the engine, the more fuel the ECU injects, thereby increasing  or decreasing the power output of the engine. When a problem is detected in the throttle system, a signal from one of the sensors triggers the  ECU into illuminating  the EPC  warning light. 


The Electronic Power Control (EPC) is just a part of the Engine Management System, which in turn is part of the overall On-Board Diagnostic II system. Normally when the a problem is detected that causes the EPC light to turns on, it also sends fault codes to the dashboard module or gateway module, vehicle model dependent. These fault codes can be retrieved by an ODBII scanner / smart phone, which are key to isolating the area of the throttle system that has failed. Most EPC light and ESP light problems will limit your Volkswagen's output power, commonly known as "limp mode".  

It is advisable that when either the EPC or ESP lights turn on, the problem associated with it be repaired timeously. A Volkswagen in limp mode should not be used to run errands, and since the car has sufficient power to drive it to  dealership or mechanical repair shop, it is best to do so. Normally once the fault / problem is remedied the EPC or ESP light will turn off. However, there are hundreds if not thousands of Volkswagen owners who have taken their Volkswagen cars into dealerships for repair, only to encounter the same EPC / ESP problem a day or two later.  Some of them suffer with EPC problems for months and I personally know of someone who had an EPC problem for more than a year. That's enough to drive the sanest person nuts.

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My W Polo classic 2003 model's EPC light is on and there's no acceleration. My VW Jetta's dashboard displays the word  EPC, now it has no power. My VW Golf diplay the letters Epc, what can I do?  My VW Golf IV cluster shows both epc and esp and it won't revv up, nor go more than 70 km/h. My VW Sirocco 2017 model's epc light has come on again. My car's EPC light is on and I don't know what to do?  

Is EPC safe?

IS EPC SAFE?

The Electronic Power Control Circuit with its EPC light virtually has every motorist annoyed globally. Most motorists seem to be up in arms over this "idiotic warning light". Yes, this is exactly what several clients have called it because they believe manufacturers added it into cars as  a "cash cow" measure, which the dealer will reset by just pressing a button and charge then through there noses. This is really not the case because there are so many dealer's mechanical workshops that have no idea how to fault find nor repair and EPC fault. Motorists have even gone as far as saying the the EPC circuit is an unnecessary addition, as the tried and tested Otto Cycle internal combustion engine has worked perfectly for at least a hundred years without it.  

Without question, the EPC light is probably the most misunderstood dashboard light plaguing motorist the past two decades. However the EPC circuit is in fact a safety feature that few seem to appreciate. But is doesn't work in isolation, it is a sub circuit of a the ECU circuit. The ECU overseas the running of the running of engine at its peak whereas the EPC circuit is specific to the torque circuit - whatever propels the vehicle and safely stops the vehicle!

For example, in older cars that used a physical cable to control the throttle; it was prone to fray and could easily get stuck whist driving at high speed. This actually happened hundreds if not thousands of times, hence an alternative was imperative. When releasing the accelerator pedal with a frayed cable the engine would remain at a high rev and make braking difficult if not impossible. Restated, an accident in the making. This will never happen with cars fitted with EPC because it uses drive by wire - which in effect is an electronic throttle control,

Some Volkswagen vehicle problems makes driving in traffic very difficult let alone dangerous due to loss of braking & steering assistance. Case in point, when the ABS warning light comes on, its more often than not a melted fuse located on the battery cover that dies from metal fatigue or caused by faulty  or  intermittent connection on the wheel rotation sensor wiring.  Or if one of the brake light burns out, the EPC circuit would determine that the car is not in a "roadworthy condition" and instruct the ECU to disables propulsion so that the necessary repairs can be effected.

The EPC circuit monitors several sensors and when anyone of them go out of whack, the EPC kicks in, to the rescue of the driver by sending the car into limp mode. Admittedly not everyone shares the sentiment that "limp mode" is a safety measure because if appears to causes more feelings of frustration than feelings of safety. There are tens of thousands of motorists who would testify to the latter, myself included. I experienced  loss of power whilst driving on the freeway with a large trucks behind me, that almost wiped me out if I hadn't swerved out of its way just in time.

I'm almost certain you've had a similar experience with your Volkswagen. My sister had such an experience with her grandchildren in the car ad she swore she would never drive a Volkswagen again.

EPC ELECTRONIC POWER CONTROL

EPC ELECTRONIC POWER CONTROL Q & A

Common causes for EPC warning light illumination

Over the past few weeks numerous questions came pouring in, really fast and furious, most of them at a loss about the EPC light on their vehicles. Below are a few of the VW owner's questions, accompanied by my answers that may have solve their EPC light problems. However, the symptom they present may be similar to your car's symptoms but the cause may not be identical, so therefore the answer may not exactly fit your problem, but it could at least but you the right track. If  you suddenly see the yellow EPC dash board light illuminate on your Volkswagen, Polo, Golf, Kombie, Jetta, Passat etc. don’t panic. 

The EPC light is amer/orange because it's an informational /warning light, whereas a red dashboard light calls for immediate attention, for example when the the oil or water dashboard lights comes on. EPC stands for Electric Power Control (EPC), and  is a computerized ignition and engine management system that can alert you to a potential engine malfunction, as well as alert you to a variety of engine issues, though most of them are fairly simple to diagnose and repair. Bearing  in mind other systems such as stability  control and cruise control can also have an effect on the EPC system.

QUESTION:- 

My VW Golf VI 2010 model shakes when I accelerate, then it suddenly looses power and the EPC light illuminates. Can you please help. What could be the cause of this  and please tell me how to fix it.

ANSWER:-

Most VW engines have a flat-plane crank, meaning the inner two pistons move up and down together, in opposition to the two outer pistons, each providing 90 degree crank propulsion. When one of the cylinders are not doing their portion of the work, the crank is unbalanced and will cause the entire car to shake. This normally happens when either an injector or a coil on one of the cylinders is misfiring. Since the EPC circuit monitors the engine torque, it will illuminates the EPC light when it diagnoses that 25% of its torque is lost. By restoring the 25% torque by replacing the faulty component, either the coil or the injector by a process of elimination, the shaking will stop. 

Then again, I experience severe shaking on my Polo 2.0 one day, for some reason o the other, two blades of he radiator fan  snapped off and the centrifugal force of the two remaining blades shook my entire car really violently. Its the first time I experience something like that and at that moment in time I got such a fright, my heart was pounding in my throat.

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QUESTION:-

I have a Golf Polo 2012 model that's been to the agents for regular diagnostic tests because its been more than a year that they've been trying to resolve the “EPC” light  problem.  The following items have been replaced but the light still comes on -
Ignition coil, Throttle Body, Accelerator pedal, Four injectors
Cambelt kit, RPM sensor .

ANSWER:- 

Since so many components have been replaced, I would suggest you upload a diagnostic scan so that I can analyse it because the above looks like guess work. There are so many things that can trigger the EPC, but don't replace anymore components until you've checked:-

1) The rubber hoses to the MAF for cracks,
2) Cleaned out the tar-like deposits in the throttle body,
3) Cleaned the idle speed control and butterfly valve with Wynn’s Throttle Body and Air Intake Cleaner, 
4) Performed a throttle body adaptation, 
5) Checked that the knock sensors are properly torqued,  
6) Checked for the correct spark gap on your spark plugs, 
7 Checked that your engine temperature coolant sensor works, 
8) Checked that your fuel cap seals properly, 
9) Checked that your fuel pump isn't noisy, because if it is, its probably pumping under the required pressure. 
10) Checked the wiring loom connecting to the pencil coils and the fuel injectors for intermittent contact. 

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QUESTION:-

Please tell me why does my Polo's engine switches off while I'm driving? When I try to accelerate there's no power and when I looked at the dashboard, the  EPC Dashboard Warning Light is on. That's when I realize the engine is not running. But thereafter my Polo wouldn't restart, not until  it cooled for a while. Then my polo will then drive perfectly normal until the next time the EPC light comes on again.

ANSWER:-

This sounds very much like an  Engine Speed Sensor problem. Normally when they do go faulty the car will not start at all.  It is common for the EPC light to come on, by which time the engine died and after about 2 hours everything is back to normal. However its seems like your Polo's sensor is just starting to give trouble. This is a hall sensor, that generates a waveform whenever it senses the rotational magnetic pulse. But when it gets too hot, it starts to fail. I've had hall sensors located inside the distributor go faulty on Opel Kadett GSI due to engine heat in peak hour traffic but after it cools down, the Opel starts and drives normal.  It seems like hall sensors don't like heat.   

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QUESTION:-

I had my Volkswagen cc R-Line's  brake pads replaced after 48,000 kilometers  but now every time when I accelerate the EPC light comes on and there's no power. I'm totally miserable because the car is now useless. Can you please shed any light on this matter?   

ANSWER:-

Dude, its more likely than not that you've picked up a wheel speed sensor problem from your mechanic. One of two things, either the plug to the ABS wheel sensor isn't making good contact / the wire from the sensor is broken off or the gap between the ABS sensor and the disk is wider than it should be. It's very unlikely that the sensors are faulty because it probably worked fine before your mechanic replaced the pads. A telltale sign is that your speedometer isn’t working because the front sensors are also the input for the speedo.

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QUESTION:-

I was cruising on the freeway and suddenly the power just cut out and there was no more acceleration and the EPC light went on. I thaught my VW Jetta ran out of fuel because the fuel gauge was on empty but it didn't because I could still drive it slowly. but it wouldn't revv up.  I took it to the agents who said it was caused by driving with a little fuel in the tank. But now the same thing has happened to me four times thereafter. What can I do because the agents say there is nothing wrong.

ANSWER:-

If truth be told, your intank fuel pump must have overheated when you were driving with an empty tank. Remember the fuel pump is cooled and lubricated by the fuel in the tank and when there is no more fuel to cool and lubricate, the pump can overheat.  Also, if there is debris in the tank, it can block the filter or pipe attached to the pump. Since this is a low pressure pump  it won't have force to clear the debris and wont be able to feed fuel to the high pressure pump driven by the camshaft. It's probably best to have your fuel line cleared under pressure alternatively replace the fuel pump.

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QUESTION:-

I have an Audi A4 with a early model 2.0T engine. For the past few weeks starting from cold in the morning has been a problem but since yesterday, it seems to have lost all power it power and the EPC light is on. With the pedal to the floor in any gear, the rpms increase but the car just won't pickup speed.  

That seem to a common issue with the older Audi A4 models. It's normally the high pressure fuel pump pawl that's busted, which probably destroyed the lobe on the camshaft as well. Sometimes the pressure of the camshaft hollows out and destroys the cylinder head. Check the high pressure at the output of high pressure pump, it it's low then  it's definitely the pump and camshaft combination.