What does it mean if the EPC warning light comes on in a Volkswagen?

What does it mean if the EPC warning light comes on in a Volkswagen?

Since the inception of the motor vehicle, several manufactures have claimed that their brand of car, has sold the most units globally. But since there is no definitive comparative yardstick to measure the exact amount of units sold,  Volkswagen claimed that their Volkswagen Beetle is the "bestselling car in history", considering they had sold more than 21 million units. To be more exact, The New York Times, date July 31, 2003 stated that the very "Last Volkswagen Beetle" manufactured was in fact number 21,529,464. 

Ford on the other hand manufactured their 1 millionth Model T's during the last month of 1915, with total sales of 15 million units produced by 1927 when they ceased production. In 1972 Volkswagen broke Ford's record when their 15,007,034th Beetle came off the production line in Puebla, Mexico. 



Be that as it may, Toyota boasts that in reality, their Toyota Corolla is the "bestselling automobile in the world", after reaching their 40 millionth unit in July 2013. But regardless of their claim, Volkswagen is undoubtedly still the "bestselling automobile in the world" seeing that the Volkswagen Beetle didn't change its shape or form since 1945 up to and including 2003, whereas Toyota used their Corolla label for eleven generations of Toyota cars, built since 1966 and this very Corolla label is still in common use. Non-the-less, statistically Volkswagen has been the best selling car globally until late 1998; meaning the Volkswagen Beetle remains the "bestselling vehicle ever". 

Enter the Volkswagen Kombi, Volkwagen City Golf, Volkswagen Fox, Vokswagen Jetta, Volkswagen Golf, Volkswagen Polo, Volkswagen Passat, Volkswagen Kombi, Volkswagen Sharan, Volkswagen  Toureg, Volkswagen Amrok, Volkswagen Transporter and the list goes on. However this entire Volkswagen fleet doesn't come without their fair share of  problems. The most common of which is probably the EPC light accompanied by limp-mode home.

What is the VW EPC Warning Light, 

The Electronic Power Control warning light, is commonly known as the EPC warning light. It's a dashboard warning indicator that suggests that there may be a problem with your Volkswagen’s throttle system. The throttle system consists of the accelerator pedal, the throttle body, traction control, cruise control, and the ECU, which is collectively called the drive-by-wire system. 
The drive-by-wire system is also sometimes referred to as an Electronic Throttle Control (ETC), roughly described as a technology that electronically "connects" the accelerator pedal to the throttle, instead of a mechanical linkage. 

In a drive-by-wire system, an electric stepper motor determines the angle of the throttle valve. How wide it opens or closes, is calculated by a —closed-loop control algorithm— software controlled embedded system built into the ECU. The ECU makes decisions based on various input data from several sensors, among which are, the accelerator pedal position sensors, engine speed sensor,  vehicle speed sensor, and the cruise control switch. The Electronic Control Unit (ECU) can also be described as a computerized ignition / engine management system  that operates in conjunction with the stability and cruise control systems. When the EPC light comes on, it means the problem is not emission related, whereas the Check Engine Light (CEL)indicates emission related problems but when it lights up, can be accompanied by the EPC light. If the EPC warning light comes on in your vehicle, it is important to have it seen to as soon as possible, because it you don't invariable it's going to trigger again when you least expect it.

EPC Car Warning Light

When the EPC light comes on in your Volkswagen, its throttle may be limited in power, yet have sufficient power to drive the car to a dealership or mechanical workshop, but it shouldn't be driven elsewhere. This is called limp-mode-home. Limp mode home is  inherent in its the software design in order to to protect the car from run-away and  its passengers from possible injury. Volkswagen cars equipped with a Electronic Stability Program (ESP) program, will display its ESP light instead of the EPC light and may automatically trigger the car into limp-home mode. 

Vehicles fitted with Traction Power System (TPS) are also prone to enter into 'limp-home-mode'  which effectively prevents software glitches from initiating or activating unintended acceleration.  In 2011 the U.S. National Highway Traffic Safety Administration (NHTSA) commissioned a team of NASA software engineers to evaluate software of late model year Toyota and Lexus vehicles, alleged to be the cause of  unintended acceleration collision, which caused the death of a passenger in a September 2007. 

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The Definitive EPC Guide 2

The Definitive EPC Guide (Continued)

For part ONE Click Here!

Having said that, in my humble opinion, the  EPC circuit with its drive-by-wire circuit and its "Limp-mode home" mode, is a value-add for modern car design; and though frowned upon by many, is a very valuable safety feature. Also bearing in mind that when the communication network is momentarily unavailable and an application that depends on it is unable to communicate, it may trigger the ECU into "Limp-mode home" and set a DTC. Exception errors do occur in  synchronous or asynchronous distributed system, where software entities act as clients or servers or both. So when where 1...n clients are requesting services via a specific protocol from typically one server; the server services the client  but  temporarily blocks its service request and data flow control, whilst other client expects a response from the server.  

If 1 client to n server communication can be established, it would certainly solve the problem but it’s currently not supported. Also remembering that the CAN bus is a serial communication network through which all modules communicate with the ECU via a Central Gateway, some uses FlexRay frames and others Lin bus or CAN, each with a differing topology, some synchronous and others asynchronous. The Central Gateway is responsible for frame or signal mapping function between two communication systems, like from LIN/MOST/CAN/FlexRay to Ethernet transport systems. However ECU gateways often have two or more internal Gateways like the Service Data Unit (SDU) gateway, Layer 3 Tunnelling Protocol (L3TP) gateway and the Signal Gateway needed for frame or signal mapping function between two disparate communication systems.

The best analogy with which to explain the above would be your cell phone. Cell phones are native Global System for Mobiles (GSM) devices with a microprocessor and its support chips, much like the automotive ECU. Cell phones support the Hypertext Transfer Protocol (HTTP) and the Wireless Application Protocol (WAP) for Wi-Fi as well as the Bluetooth communications protocol through a "Gateway" which translates it to a common data stream native to the Cell phone operating system. 

So, while you’re downloading an email and the phone rings and you answer; the email download temporarily stops but will resume when the call is terminated. The same applies to a Bluetooth file transfer which will be interrupted even possibly terminated when a phone call is answered. However, not all services are prone to such interruptions because some services are inherent to the design. For example, when you’re listening to music on your cell phone and you answer an incoming call, the music is temporarily suspended until the call is terminated then the music will resume. 

This function is purposely part of the design whereas exception errors are not and are more prone to happen with asynchronous communication, caused by propagation delays. This is what also happens when the ECU inter communicates with other modules and when the messages are not delivered within a prescribed period of time, can cause the car to go into "Limp-mode home" . So if for some reason the radio that is a non-essential service is hogging the network bus, and you step on the brake which the ECU will undoubtedly detect but the brake light didn't illuminate within the expected response time, which the ECU will also detect, then the car may go into "Limp-mode home" . 

Or you could hit a speed bump in the road at high speed and bounce back onto the road; the thump if hard enough or loud enough to trip a knock sensor would cause the car to go into "Limp-mode home" . Or you could have just done some high rev spirited driving to cause the car to go into "Limp-mode home" . One consolation is that, when the ignition is initially turned on; right before the car is started the ECU does a self-test to verify that all’s well, and if that is the case, the car will start and drive normally. 

However, if the self-test fails, one of the caution lights may remain on. It could be either the EPC light or the Check Engine light or perhaps both, or one or both could be blinking, which is a sure sign that you may have a problem. Once again, a diagnostic scanned would be the most informative way of establishing what the problem is. But I’ve encountered car owner who took their vehicles for diagnostic tests and no errors were flagged, so in some cases may be a futile exercise. 

Having said that, if you are stranded along the road side, the best would be to reset the ECU by removing the battery earth terminal for a minute or two, but make absolutely certain that you have access to your radio / DVD code before  you disconnect. Whatever errors occurred prior to this will be safely stored in the ECU non-volatile memory and may be checked when a diagnostic scanner is available but all stored values will be lost.  The downside of doing this, is that an additional error would be flagged because the battery (+30V) supply was interrupted, and now the ECU has to relearn your driving style.

ECUs are fairly robust and are more-likely-than-not the cause of your EPC problems, though unlikely but not impossible.  The most likely component in my humble opinion that would cause constant and annoying EPC problems would be the wiring harness. Not the actual wires, unless they are frayed and damaged by rubbing against the chassis but rather its edge connectors. 

The ECUs and associated modules each have multi-pin connector that’s tin plated and can become intermittent due to the constant vibration of the car. Copper contacts also oxidizes fairly quickly, so to prevent this from happening, they are tin plated which provides for a low resistance, good contact surface. However when water enters this connection, especially in the presence of a voltage or current flow, the contact normally turns black or corrodes green, impeding continuity hence connectivity. 

A poor vehicle ground connection is another culprit that can intermittently trigger the EPC light without leaving a DTC.  A blown tail light / brake light bulb can also cause the EPC light to turn on without leaving a DTC. Always make sure that the replacement is a 12V 21/5W bulb because the wrong bulb will also cause the EPC to trigger also without leaving a DTC.  A faulty brake-light switch (DPST) is also commonly known for triggering the EPC light and sometimes causes the 10A fuse to blow. 

So, when the brake is applied and the switch throws, its contacts reverse, meaning the normally-open contact closes and the normally-closed contact, open. If there is a delay in the switching time, even as short as .5 of a second, the EPC light will trigger, without leaving a DTC.  A tell-tale sign that the brake-light switch is faulty or that the fuse is blown; is that the Cruise Control appears to be faulty. Since they are both interconnected, the Cruise Control is reliant on a voltage provided through the brake switch. 

DTC can often be intermittent or sporadic so it’s best to ignore those, in preference of repairing those that are permanent. In so doing, they may have interrelations and the sporadic ones may disappear after the permanent errors are fixed. So, it’s best to perform a diagnostic scan, preferably an autoscan with VCDS first, then delete all DTC in the process. Thereafter save this scan and printout a hardcopy to store with the vehicles registration papers. 

The importance of this printout is that it’s a reference to all the modules coding, and if something is inadvertently changed, there would be an unalterable record to refer to. Once done, and as mentioned above, disconnect the battery's negative terminal then disconnect the positive pole and place the battery on charge for about two hour.  Replace the battery by first connecting the positive pole then lastly the negative pole.

 By following this sequence you will prevent damage to the electronics modules strew throughout the car.  At this point, all pre-learnt and all stored values would have been erased from the ECU. Essentially all the control modules would have been completely reset, restarting with a clean slate.  After starting the engine and driving the car for a short distance, check to see if any DTC have been flagged.

Resetting an ECU occasionally is a good thing, because any and all electronic equipment with a microprocessor can experience an unrecoverable error or an internal parity error or fail a cyclic redundancy check and requires a "cold" system restart. Computer  memory (RAM) also experience memory read/write errors, interrupt or address errors and general protection errors; so  when the ECU is reset/cleared, along with its non-volatile memory, the memory (RAM) is also reset.  AUOTSAR and its core partners are trying their utmost to rectify such problems in automotive ECU, but until they do, we will have to contend with EPC problems.

To read the first part... click here.

The definitive EPC guide

The Definitive EPC Guide

The following is the definitive guide to the Electronic Power Control (EPC), but before we continue, let me expound on what this guide is and what it's not. The very purpose of a guide is to provide information; to aid, give direction, to grant assistance, to facilitate, to support and to help you towards a solution or provide you with an explanation or an answer. However, even though this guide may furnish you with several answers, not every question can be satisfied by the same answers, though it could possibly steer you in the right direction. Hopefully you'll find this EPC guide definitive enough to provide you with the necessary knowledge to fix your Volkswagen, Audi, Seat or Skoda's EPC problem. Or at the very least, steer you in the right direction or share the lingo with which to discuss your EPC problem with your mechanic. 

But before I continue, let me first explain what EPC is. EPC stands for Electronic Power control and is a subsection of the OBDII. OBDII sometimes writen as OBD2 stands for On-Board diagnostics 2, which is composed of mandatory equipment installed in every motor vehicle manufactured since 1996. The purpose of this real time OBDII system is to control harmful exhaust emissions, by rigorously controlling the moment of combustion as close to the Stoichiometric  ideal as possible. Stoichiometric combustion is therefore controlled by an ECU (Electronic Computer Unit) in conjunction with the mass air flow components and the lambda oxygen sensors through constant feed-back in order to increases or decrease the short term fuel trim.  

To define an ECU instance, one could say that it consists of one microcontroller with its peripheral chips and its configured  software application.  This also implies that if more than one microcontroller in packaged in the same ECU housing, each microcontroller requires its own description of said instance. As such, each ECU forms an integral part of the OBD2 system, with strong interaction between hardware sensors and actuators; constantly monitoring and controlling several other engine components to provide the best engine performance at the most efficient fuel use , as well as provide the driver with the best driving experience. Another part of the OBD2 system is its network bus which interconnects several distributed computerized modules, ECUs, sensors and actuators, collectively geared towards better functionality and passenger safety. But before I get carried away, let me return to EPC.

The EPC sub circuit when triggered turns on the EPC light or LED which displays the letters EPC quite brightly in the display console. Many VAG car owners have asked “What's the meaning of EPC warning light when it comes on in a Volkswagen"? Short answer; it’s just a caution light like any other warning light, drawing your attention to a possible problem but with one exception. This exception is that the EPC light is an amber/yellow light and not red. 

Much like road signs that have different colour boards for danger/warning than for  prohibitory/restrictive signs  or than for  service/information  purposes, the automotive sector uses, red lights to signify danger/warning which warrants immediate attention and amber/yellow lights for informative/attention which also requires your attention, though not immediate. When the ECU detects that the engine oil is low for example, it turns on a red light – red oil-can image – which implies that it's dangerous to drive the car in that condition because its engine could seize and therefore begs you to respond and remedy this situation immediately. 

Likewise when your handbrake in engaged, a red light – red disk with a P or exclamation mark inside –  is displayed, implying that it's dangerous to drive with the handbrake engaged, expecting you to release it immediately. Disregarding this red light and driving the car with the handbrake engaged could cause the brake pads to overheat and fail to function when needed but that’s to say if the car would even move from its stationery position with the brake engaged. Headlights on the other hand are indicated by a green dashboard light or a blue dashboard light when the Brights are switched on, neither implying danger nor attention. So in that sense, the yellow EPC light is just an attention light, much like the yellow safety-belt-light provides information that you haven’t bucked up or the yellow reserve-fuel tank-light informing you that you would have to add fuel shortly.  

Very importantly, a yellow light doesn't mean disregard, because disregarding a fuel tank yellow light could leave you stranded without fuel along the roadside. Or disregarding the yellow seat belt light could result in a traffic fine for non compliance to traffic laws. Therefore do not disregard the yellow EPC light and have the possible problem seen to at your earliest convenience. I hear you asking “What can I do when the Yellow EPC light comes on"? Normally when the EPC light comes on, it is accompanied by "Limp-mode home" and sets a DTC in the ECU non-volatile memory. So you need to have your car scanned with a diagnostic tester to determine and analyse the DTC error. 

I hear you asking "What is limp mode". Short answer, when the ECU detects a problem in the toque circuit it prevents the engine from revving above 2000rpm. In effect, it limits the electronically controlled throttle valve – Drive-by-wire – from opening wider.  “So what’s this Drive-by-wire thing”? you may ask.  Well the drive-by-wire circuit is a sub circuit of the EPC circuit and it simulates an accelerator cable, where the depression of the accelerator pedal is monitored by the ECU which in turns drives the throttle body valve open, in unison with the pedal action without any physical cable connection. Essentially it's an electronic version of an accelerator cable /acceleration process. Its electronic circuit is composed of dual sensors constantly monitored by the ECU, and any interruption in its data, will more-likely-than-not trigger "Limp-mode home", turn on the EPC light and set a DTC.

The ECU also constantly monitors the dual sensors in the throttle body as well as  the motor that drives the throttle body butterfly valve. Any interruption in its data will more-likely-than-not trigger "Limp-mode home", turn on the EPC light and set a DTC. This is a safety feature built into OBD2 to prevent the car from going into runaway mode with the possibility risk of injury. Image what would happen when a frayed accelerator cable jams inside its armoured sleeve, unable to decelerate the engine whilst travelling at a speed in excess of 72kph. Considering more than 50% of all accidents in rural areas happens at speeds between 72kmph and 80kmph whereas 70% of all fatal crashes on the freeway occurs at speed of 100kmph or higher.

Continue to part TWO.... Here!

AUTOSAR and the automotive black box.

AUTOSAR and the automotive black box.

Within the next few days the 11th AUTOSAR Open Conference will be hosted at the Portman Ritz-Carlton in Shanghai China. The date of this event is scheduled for the 6th - 7th November of 2018 and that's a mere 8 days from today. At this conference AUTOSAR experts from within the automotive industry will present their  "Future Automotive System Architecture", both  the  Classic and the Adaptive Platforms. Both specifically developed to support high performance microprocessors, with improvements in the safety and security demands for autonomous driving vehicles, aka self driving vehicles. Essentially all motor vehicles of the future.

AUTOSAR logo

They advocate that, due to the latest connectivity requirements and the enormous possibilities available through the “Internet of Things” it is mandatory to upgrade the current system architecture of automotive electronics. Especially when considering their new applications like advanced driving assistance, electric mobility, autonomous driving, V2X (vehicle-to-everything communication) and off board connectivity over the air (OTA).

So what does all this mean in layman's terms. Well, it is AUTOSAR's attempt towards automotive standardization and for the development of smarter, safer and more secure vehicles in the future.  So, who is AUTOSAR you may ask? The short answer; AUTOSAR stands for (AUTomotive Open System ARchitecture) and is a worldwide development partnership of over 250 vehicle manufacturers, suppliers, service providers and companies from the automotive electronics, semiconductor and software industry. Their collaboration  and  collective objective is to agree on a "Standardized Software Framework for Intelligent Mobility" and implement it, as the way forward. 

An incomplete overview of the AUTOSAR Runtime Environment
and how components plug into it

This would simplify replacement and updates for software and hardware, which essentially forms the foundation for reliably controlling the growing complexity of electronic and software systems in today’s and future vehicles. The AUTOSAR alliance was formed in June of 2003 and comprises of  9 "Core Partners"  viz, BMW Group, Volkswagen Group, Continental, Daimler, Ford, General Motors, the PSA Group and Toyota. In addition there are some 43 Premium members as well as another 112 associate members collectively contributing to the motor industry.

Standardization is a good thing and when coupled to "open architecture" is even better. Case in point, Linux is open source and it revolutionized computing.  Linux was selected for its ability to run on many and various makes and models hardware boards. Besides, Linux more-likely-than-not has the widest device driver support of any other operating system on the planet. As such,  Linux became the de facto application software for developing specialized embedded devices in consumer electronics. For example, personal video recorders (PVRs), wireless access points (WAPs), personal digital assistants (PDAs),  Global positioning systems (GPSs), in-vehicle infotainment (IVI), routers, switches, set-top boxes, navigation systems, home automation systems, car dashboard sytsems, security appliances, etc. 

Linux is such a highly flexible platform that makes it relatively easy to port to other hardware architectures. As such Android relies heavily on its level of hardware abstraction (HAL). Android is an open source Linux-kernel-based operating system which revolutionized handsets far beyond phones, tablets and TV's. When Google acquired Android, they created the Compatibility Test Suite (CTS), which defined what OEM's handsets should comply with, to be Android-compatible.  This CTS is just just a HAL (hardware abstraction layer) for the Android stack. 

In the same vane AUTOSAR intends an open and standardized software architecture for automotive electronic control units (ECUs). It's RTE will act as a HAL sitting on a layer between the application software and the Hardware.  It would form a standard ECU (black-box) usable by all manufactures with a layered software architecture that would reduce individual expenditures for research and development while mastering the growing complexity of automotive electronics. 

The AUTOSAR operating system is also backward compatible with OSEK/VDX (ISO 17356) and consists of Basic Software Modules, Application program Interface (API), Specification of ECU Configuration Parameters (XML), Standardization Template, Generic Structure Template, Interoperability of AUTOSAR Tools.  Hopefully the AUTomotive Open System ARchitecture would do for cars and safety in general what both Linux OS and Android OS have collectively done for consumer electronics as a whole.

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.

Volkswagen Ignition System

Did you know that the electronics industry has had the fastest growth in the shortest amount time, compared to all other industries 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 the industrial revolution. Much later Samuel Finley Breese Morse invented the single-wire electric telegraph system and developed the Morse Code. And sometime thereafter Alexander Graham Bell invented the first practical telephone system and their collective efforts, without discounting anyone else's efforts, changed telecommunications forever. 

Added to this, ancient records show that the first streets of Baghdad were paved with tar, and that the Babylonians used asphalt to construct the walls and towers of Babylon. Even The I Ching bears testimony to the fact that the cites of China used oil extracted in its raw state before refining was first discovered, during the first century BCE. By implication, tar, crude oil and pitch, were used as a sources of fuel for a very long time before paraffin was distilled from it. When this finally happened, the thin distilled paraffin was commonly used as fuel for lamps whereas the thicker residue was used to lubricate machinery. Soon after or in and around this time, when oil/fuel was extracted from coal, Étienne Lenoir successfully innovated the internal combustion engine followed by Nikolaus Otto who became famous for successfully developing the compressed charge internal combustion engine - the Otto engine. 

Now Henry Ford on the other hand wasn't an inventor nor an innovator, by any stretch of the imagination, as many are led to believe. 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 could clearly say that their collectively 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. 

Electronics

However, when the mechanical inventions of the Industrial revolution, is compared to modern day electronics, it stands out like a global coup. Initially there was the vacuum tube aka the electron tube, colloquially known as a valve. It gave way to semi-conductor devices as a whole. Transistors and gave rise to the analogue Integrated Circuits (IC) aka chip, followed by Transistor/Transistor logic TTL chips, followed by  digital semiconductors like complimentary metal oxide  semiconductors (CMOS) chips, ROM (digital read only memeory), RAM (random access memory) chips, EEPROM (electronically erasable programmable read only memory) chips. 

This was followed up by large scale integration (LSI) chips and Very Large Scale Integration Chips (VSLI ) chips. With the advent of multi-layer circuit boards and surface mounted technology, microcontroller (system on a chip) SoC and  microprocessors (µP) became pervasive. Assembler language for chip families was developed and compiled to high level languages for programmable chips while software programming sat at the heart of most electronic devices and electronic systems. Communication protocols were developed and networks of various types became mainstream. All of this happened in 50 years as opposed to 200 years as mentioned above.

Volkswagen Ignition System

So you may ask, what has all this history to do with Volkswagen, Audi, Seat and Skoda and for that matter all vehicles from plains to trains? Well the short answer, everything! Much like the industrial revolution with its mechanical enginuity;  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 of old, so did the electric wires, and electrically controlled gauges, and relays switches in cars and planes multiply.

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, 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 a distributor but was computer controlled, and by the 90's the computer evolved to an ECU, replacing the coil with a power pack. However, with the constant and ever increasing price of gasoline and looming environmental concerns about vehicle exhaust pollution; the automotive industry then accelerated its R & D into newer and denser, more fuel efficient engines and power-train systems capable of higher power output with enhanced robustness. 

With the demand for higher-km/litre vehicles, Auto Ignition System needed to undergo an extreme revolution to produce a more  advanced Ignition Systems. So, by the 90's an Insulated-Gate Bipolar Transistor (IGBT) was introduced into the Ignition System as a discrete component connected to the ECU. It essentially replaced the bi-polar transistor used in older systems. 

Insulated-Gate Bipolar Transistor 

An Insulated-Gate Bipolar Transistor (IGBT) is a fancy transistor, a semiconductor that functions like a switch.  Unlike mechanical points, a semiconductor switch doesn't have moving contacts and is thus referred to as a solid state switch capable of handling Voltages between 600 Volts and 3300 Volts. So in a nutshell and IGBT is a fast solid state switch capable of switching speeds between 6 ns and 125 that and can be remotely controlled.  It is thus controlled by the ECU via a driver module. The 12V DC traverses the coils winding and its negative side is connected to the collector of the IGBT which switches it to earth giving rise to induction in its secondary winding that produces the spark. Switching on and off also creates heat in the collector/ emmiter junction, cable of withstanding maximum junction temperatures of 150°C and 175°C. So as can be seen, an IGBT its just a fancy transistor, it is the latest technology needed for engines to operate at higher compression ratios that need higher spark plug voltage that can emit greater energy to ignite lean air and-fuel mixtures.

Post Y2K  technology

Starting from Y2K Ignition Systems were all ECU based, but the power packs of the 90's were replaced by dedicated coils per engine cylinder,  yet making use of an Insulated-Gate Bipolar Transistor (IGBT) as discrete component but connected to the ECU. From 2004 to 2010 the discrete Insulated-Gate Bipolar Transistor (IGBT) integrated into individual Ignition Coils evolved to the all new Smart IGBT connected to the ECU. In later technologies the discrete / Smart IGBT evolve into a IGBT Module also integrated into each of the individual coils. 

What this implies, is that each spark plug have its very own coil completely independently switched by a Smart IGBT module driven by the ECU to an extremely tight tolerance. The ultimate objective is, that the ECU, whilst maintaining absolute  stoichiometricity,  triggers the Smart IGBT module that in turn fires the spark plug at the precise moment to attain  absolute combustion.

The accurateness of the entire ignition timing process is  determined by the ECU. Its internal programming tightly controls  ignition timing process yet subject to inputs from several engine sensors as well as engine speed, torque and  temperature. Should the spark occur too early, the resulting combustion chamber pressure, then applies force to the crankshaft before its force can be transformed into continued rotation. This could cause pre-ignition. Should the spark occur too late, the combustion chamber pressure peak weakens rapidly as the chamber volume rapidly increases as the piston moves downwards. This normally results in  incomplete combustion, causing possible  knocking.  Both pre-ignition and knocking are totally undesirable and the most common cause of hydrocarbons - unburnt fuel exhaust white smoke. This unburnt fuel igniting in either the intake manifold or the exhaust system would result in back-firing.

Ignition Error Codes

Any such undesirables would trigger a DTC error codes in the P0300 range. P301 misfire cylinder 1, P302 misfire cylinder 2, P303 misfire cylinder 3, P0304 misfire cylinder 4. This can be extrapolated up to P0312 for a 12 cylinder engine. In the same vane, every component involved in delivery of a spark to the relevant combustion chamber can cause misfires. The coil can present a misfire, the spark plug can cause a misfire, the  wiring  between the ECU and the coil can cause a misfire, the Smart IGBT module can cause a misfire, the IGBT driver can cause a misfire and even the IGBT itself can cause a misfire.

Volkswagen_Polo

Volkswagen_Polo

During the winter of 2018, the Western Cape hasn't received a similar volume of rainfall as it did in previous years, thus draining its reservoirs to its last 10%. So, due to water scarcity a drought alert  was raised, along with the price of water. Water restrictions were implemented, water was denied, rain water was caught in Jojo tanks by many. Grey water became a buzz word and people lined up at the aquifers to collect drinking water.  In a nutshell we had a water crises and much like the price of water, the price of fuel in South Africa is also staggering.

Staggering isn't perhaps the most appropriate word  to use in this case because in essence, staggering  implies stumbling, almost falling rather than constantly rising. So I'm going to resort to words like astonishing, outrageous even scandalous. Yet this hasn't impeded car sales in the very least because cars are being sold in huge numbers monthly, despite the economic situation in SA. Not to mention that President Zuma was impeached and removed from office causing both Moody's and S&P to downgrade South Africa's foreign and local currency to junk status. Then there is also South Africa's unemployment rate that borders on 27%, followed by its  crime statistics that has somewhat decreased by 1.8% comparative to 2015/16, inclusive of vehicle theft.

Meanwhile the VW Polo reigns supreme, as the most popular and best-selling passenger  car in South Africa, closely followed in second place by its cousin,  the Polo Vivo.  The Toyota Corolla, Auris and Quest sales comes in third place, closely followed by its cousin the Etios that took sixth place.  Then there is the Kia Picanto followed by the Renault Kwid followed by the Hyundai Creta. 

The importance of this observation is that all these cars are smaller  than the average medium sized family car. The expectancy is that being smaller, they would also be more fuel efficient but that's certainly not the case. It turns out that the Ford Fiesta 1.5 TDCi Trend, the the Fiat Tipo 1.3 Multijet Easy, Fiat 500, the Peugeot 2008 1.6 HDi Active and the Fiat Panda 0.9 TwinAir Easy are the most fuel efficient smaller cars on the road respectively. But their fuel efficiency is liked to impeded functionality, cramped seating with hardly any boot space.

Why Buy VW Polo

People buy VW Polo's for its sophisticated look and feel, its overall build quality and its youthful appeal, its comfortable seating and its lavish boot space. Polo also delivers superior performance and is more pleasing to drive. They are affordable both new and second-hand and cheap to insure. The Volkswagen Polo brand has been around since 1975 and is now in its seventh generation and is also sold as the Skoda Fabia and the SEAT Ibiza. 

It just makes economic sense to drive and own a VW Polo because its spare parts both used and new are in abundance. The Polo TDI BlueMotion takes fuel efficiency to a new level and is one of the most fuel-efficient non-hybrid cars in SA, employing the same 1,0-litre turbo triple as the Audi A1. Beside VW offers a three-year, 60,000-mile warranty as standard on every Polo. Though not as fuel efficient as the match-box Fiats mentioned above.

So, considering the ever rising price of fuel, its just a matter of time before every household would want to store some in Jojo tanks underground to get a reprieve from paying  these outrageous and scandalous fuel prices. If you want a fuel price alert when it increased .... and possible decreases, click here!

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.