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.

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?  

Automotive Electronic Components

Automotive Electronic Components

Admit it or not, we all love the new creature comforts of our modern day cars, all of which have become increasingly sophisticated.  Those seat warmers in the cold of winter, the climate control in mid summer, the air suspension on those bumpy roads, the infotainment systems with integrated GPS so that we never get lost again; and the on-board video player for those times we had to patiently sit and wait in our cars for our loved ones. ECU controlled fuel injection put an end to idling the car in the morning to get it to the appropriate operating temperature. Power steering and assisted parking makes both driving and parking a breeze. ABS and traction controls ensures that your car stops and corners without incident. 

Not to mention cruise control, the increased horsepower, the additional  safety features and the overall improved spatial comforts. And the list goes on. All of this was made possible by electronics, in the name of safety. Safety in the form of Safety Restraint Systems (SRS), Front and side airbags, early crash sensors and active front seat head restraints, to  mention but a few. 

On-Board Modules

Electronic engine management systems, carputer modules, telematic systems and other electrical components constitutes a sizeable percentage of our cars, collectively affording us the aforementioned comforts and conveniences. Besides, modern cars are loaded with code; and the number of electrical components in modern cars are on the rise, constantly and consistently increasing in number, and their failure can more often than not affect our driving safety. These electronic components can easily malfunction, either due to water ingress during wet weather conditions, or due to excessive vibration due to bad road surfaces, or just through general wear and tear. Most of these components are cheap and relatively easy to repair and replace but isolating the correct one can sometimes be trying. In a nutshell, modern day cars are seriously complicated, since they are not just computers on wheels but entire computer networks on wheels. Be that as it may, it is a well known fact that computers do crash, software have glitches and networks go off-line.

How safe is safe?

But, the million dollar question remains; are these electronic devices really safe or are they as safe as the car manufactures would like us to believe they are.  How safe is it when you're overtaking on a single lane highway at 100km per hour and the car goes into 'limp mode' or the engine just switches off and refuses to restart?  How safe is it when the steering wheel airbag explodes directly into your face for absolutely no reason? Its air pressure wave that's louder than a gun, is bound to temporarily deafen you and the smoke enveloping you would certainly disorientate you. These factors can contribute to you loosing control of the car through no fault of your own or even loose your life.  

How safe is it when you suddenly and momentarily loose steering control at high speed or whilst driving in fast moving traffic when your car doesn't react to your steering direction?  Or, how safe is it when your steering wheel suddenly goes stiff when turning (temporary loss of power steering)? How safe is it when your car randomly starts to jerk and switches off on a deserted road at night? 

How safe is your VW really, considering certain Jetta, Golf and Audi A3 models are being recalled for fuel leaks that can cause potential engine fires. Case in point, German supplier Continental Automotive GmbH has been supplying fuel tank polymer flanges that crack to five OEM parts supply companies at least 11 auto makers, VW, Audi and Porsche included.  What this means is that 
there are millions of cars of all makes and models that may have leaking fuel issues as we speak.

Electrical sub systems

As mentioned above, modern cars, can have as many as 200 small embedded electronic control units, better known as  (ECUs). Each module is in fact a fully fledged computer in its own right, overseeing one subsystem. Collectively they  have several functions, ranging from controlling the engine and or transmission, to controlling the immobilizer, to controlling the air bags, to unlocking doors, to controlling the radio, to managing the ABS, to managing the cruise control and such like. 

Most of these computer modules have input switches and or input sensors that can detect variables such as temperature, air pressure, braking, steering angle, voltages. All these computers are connected to a centrally networked  CAN bus that carries constantly varying data between them, in order to manage the car as it is being driven. The upside of this, is that the car can virtually drive itself but the downside is that when some essential module does go faulty, it would most likely shuts the car down which may also turn out to become an expensive repair.

Automakers are becoming more like 
assemblers and less like manufacturers

Essential components like headlights and spark plugs, ignition leads, wiring harnesses, relays and switches  can often be the first to go, but they are more electrical than electronic. Whereas the following list of sensors and actuators are totally electronic.

Air mass sensors (MAF) - electronic
Camshaft Position sensors - electronic
Crankshaft Position sensors - electronic
EGR Valves  - electronic
Knock sensors - electronic
Lambda (oxygen) sensors  - electronic
Throttle position sensors  - electronic
Wheel speed sensors  - electronic
Ignition Coils  - electronic
Glow Plugs  - electronic
Coolant temperature sensors  - electronic
ABS  actuators  - electronic
Injection valves - electronic
Solenoid valves - electronic
Anti-theft alarm  - electronic ... and the list goes on.

Since Automobile production requires several thousands of parts, most of these parts are not manufactured by the car maker but are supplied by auto suppliers. Hence automakers are becoming more like assemblers and less like manufacturers because Auto Megasupplier's  contributions have drastically increased from about 60% in the mid '90s to above 85% in 2017.  Among these auto megasuppliers are companies like:-

Robert Bosch supplies (Gasoline and diesel systems, chassis system controls, electronics,  exhaust gas turbochargers, steering systems, starter motors and alternators,   etc), 

Draexlmaier Group (wiring harnesses,  interior systems, cockpit and door modules, etc.),

Royal Philips Electronics (Lighting, car radio integrated circuits, liquid crystal displays, etc.)

Infineon Technologies (Microcontrollers, intelligent sensors; power semiconductors, etc.)  

Hella ( Electronic & lighting components, etc.)

DuPont Automotive (polymers, elastomers, specialty chemicals, lubricants, refrigerants, etc.) 

SKF Automotive ( Bearings, seals, clutch assemblies, SKF Automotive drive-by-wire systems, etc.) 

Valeo SA (transmissions, Micro hybrid systems, etc.)  

Magneti Marelli (Lighting, powertrain transmissions, electronics, suspension systems,  shock absorbers, exhaust systems, plastic parts, etc.)

Continental AG (Instrumentation, stability management systems, chassis systems, safety system electronics, telematics, powertrain electronics, interior modules, etc.) 

Eberspaecher Holding GmbH (Silencers, catalytic converters, particulate filters, manifolds, vehicle heaters, electrical vehicle heaters, electronics, climate control systems, etc.)

CITIC Dicastal Co.  (Aluminum alloy wheels, aluminum casting parts, etc.)

Mobis North America (Chassis, cockpit & front-end modules; ABS, ESC, MDPS, airbags,  LED lamps, ASV parts, sensors, electronic control systems, hybrid car powertrains, parts & power control units, etc.)

That being said, there are so many of these components from auto suppliers that are troublesome. For example, batteries, starter solenoids, diodes and alternator voltage regulators and relays. Considering that the alternator is the heart of  your vehicle's electrical system and that the electrical load has substantially increased due to the glut of extra electronics, I would think that some manufactures would at least have a second alternator for redundancy. Even perhaps a redundant network so that an alternative data path is  available if the wiring harness goes faulty. Or even dual temperature sensors, or dual camshaft sensors, etc. It would do marvels for reliability.

Volkswagen is recalling some 766,000 cars globally for a software upgrade to their "anti-lock braking system".

Volkswagen is recalling 8.5 million diesel cars across the European Union  due to the "emissions scandal".

Volkswagen is recalling some 90,000  gasoline powered VW Beetle, VW Golf, VW Jetta and VW Passat with 1.8T or 2.0T engines sold between 2015-2016, because the rear camshaft lobe has the tendancy to unexpectedly snap-off from the camshaft resulting in "loss of vacuum to the brake booster", implying inefficient braking and an increased risk of a crash.

Volkswagen recalls some 280,000 cars for fuel leaks.

Honda recently recalled 1.2 million  from the 2013-2016 model Accords years, citing 'faulty battery sensors'.


Ford South Africa recalled 2.0-litre diesel-powered Kuga SUVs to resolve a potential "brake problem". 

VW electric fuel pump

VW electric fuel pump 

VW electric fuel pumps are troublesome and VW, Audi, Seat and Skoda cars are notorious for fuel pump problems. Fuel pump problems commonly affect the Volkswagen Polo Classic 6n, the VW Polo 9N, the VW Bora, the VW Passat, the VW Sharan, the VW Caddy, the VW Golf, the Volkswagen Touareg  and the  VW Beetle, among several other. Its effects can range from intermittent no starting to stalling whilst driving, though most clients would complaint that the car jerks and stall and then just shuts off. However it's not always the fuel pump that's to blame. 

VW fuel pump relay

The VW fuel pump relay is another culprit that goes faulty or rather its external contact terminals tend to burn. So if your car wont start, give the Fuel Pump Relay #409 (1J0 906 383 C) or #410 (6N0 906 383A) a knock or two with a screwdriver handle and should the car start, then it's most likely a bad contact on one of its 7 spade terminal. Remove the relay and see if any of its terminal pins have burnt brown. If not, the relay's internal contacts are probably faulty and needs to be replaced. One consolation is that the relay is fairly cheap and it can be bought on-line at ebay.com for as little as $15. However, a VW fuel pump price on the other hand, is ridiculously priced especially  considering I've had a clients who had to have two fuel pumps replaced in under 9000 km. I don't think they are quality pumps.

When our VW Caddy's fuel pump started to give-in, it presented itself as an occasional engine misfire when pulling away from a stop street or traffic lights. The engine misfire became progressively worse over time, so it was booked-in for a service, for spark plug replacement, oil drain and oil  filter replacement, etc.  At this time we didn't know that the engine misfire was caused by the fuel pump. The day the Caddy was returned, it drove fine for the first two hours then started to misfire as it did before, but thereafter the fuel pump started sounding like a hoover vacuum cleaner. 

I knew it was the fuel pump because I've heard this sound before on both a Polo 1.4 Trendline and a Jetta 1.8 which at the time turned out to be the fuel pump. Anyway, the noise from the fuel pump was really high pitched and annoying, After several hours of driving it became unbearable so the Caddy went back to the mechanic who then diagnosed the fuel pump as faulty. After the fuel pump was replaced the noise disappeared and the miss was gone as well. My friend also  encountered the "hoover vacuum cleaner" with his Caddy but after a few days it just disappeared, so now he occasionally experiences starting problems.

VW  Fuel Pump Relay 409 / 410

VW  Fuel Pump Relay Part # 1J0906383B (409) is a 12V 40A relay with 7 spade terminal connectors, 2 Wide, 2 Standard and 3 mini. The same relay is  installed in VW Polo Mk3, VW Jetta, VW Golf Mk4, VW bora,VW beetle, Audi A3, Audi  TT, Seat Leon,  Skoda Octavia,  VW Sharan and VW Passat, etc.


VW  Fuel Pump Relay Part # 6N0906383A (410) is installed in VW Polo 6N, VW Golf Mk4, VW Lupo 6X, Skoda Fabia 6Y, VW Sharan 7M, AUDI A2, SEAT Arosa, SEAT Alhambra, VW Golf GTI, VW Passat and VW Polo Mk3, etc.

Replacing a fuel pump

Remember that the VW electric fuel pump relies on fuel passing through it for both cooling and lubrication. If or when running the fuel pump dry, fuel starvation can accelerate  internal component wear and may cause  the fuel pump motor to overheat and burn out. Electric fuel pumps run from the moment the ignition is switched on, so its fairly obvious that after a few years of operation their armature bushings, gears, commutator and brushes will suffer wear and tear, causing a gradual loss of pressure. Loss of fuel pump pressure commonly causes the "EPC" light to come on. A fuel leak or an Evaporative Emission System (EVAP) leak would also turn on the "EPC" light as well as the "Check Engine" light because the low inlet manifold pressure would upset the engine's air-fuel ratio and degrade engine performance and reduce fuel efficiency.  It would also diminish  power and acceleration, and possibly even cause stalling.  So if you need to replace your VW electric fuel pump, make absolutely sure you depressurize the fuel system before disconnecting the fuel lines. The easiest way to do this is to remove the fuel cap, remove the electric fuel pump fuse or relay and crank the engine a few times. 

Faulty Fuel Pump Flanges

There is currently a VW / Audi fuel pump recall, though its not necessarily the pump that's defective but rather faulty flanges manufactured by German supplier Continental Automotive GmbH. Apparently they've been supplying VW, Audi and Porsche with flanges that seem to crack and cause fuel leaks and potential fires. Apparently Continental sold the potentially faulty flanges to eleven automobile manufacturers and five OEM parts supply companies. Audi, Ford,  Fiat Chrysler, General Motors,  Jaguar-Land Rover, Lamborghini, Mercedes-Benz, McLaren, Porsche, Volvo and VW are just some of the automakers who used these industry-standard polymer flanges but other automakers may possibly also be at risk. 

Meanwhile Volkswagen, Porsche and Audi already recalled nearly a half-million vehicles because of leaky flanges, that cover fuel tank openings and is used for the fuel pump and other items. U.S. safety regulators are currently trying to track down gas tank flanges that may crack and cause fuel leaks on what could be millions of cars of all makes and models.

Continental Automotive GmbH supplied millions of fuel pump flanges to 11 car makers that can cause a potential fire. Is you car one of them?

— Faried (@Syba_seca) July 10, 2017

My EPC light

My EPC light

If you've had your VW, Audi, SKODA or SEAT for a while, you're probably familiar with the EPC light and already experienced its wrath. If you haven't encountered the EPC warning light as yet, then you are definitely one of the lucky ones, because I know of several VW Polo, Seat Ibiza,  VW Jetta, VW CC, Passat, Audi A3, Audi A6, Seat Leon and even Porsche owners with odometer readings as low as 1500 Kilometers, who got spooked by the EPC light when it first stuck. This EPC light is known to trigger instant panic and fear in many VAG car owner, and I don't blame them, since it can be a scary and dangerous experience, especially when the car goes into limp mode when you're overtaking or the engine just dies when exiting a freeway  off-ramp or when entering a highway on-ramp during peak hour traffic.  

Electronic Power Control

However, if you have no idea what an EPC light or an EPC fault is, nor why this warning light turns on, then you should do yourself a solid and continue reading. In a nutshell, the EPC warning light is a standard feature in all ODB-II compliant models of Volkswagen, SEAT, SKODA and Audi vehicles. Most of them, are fitted with 'drive-by-wire' technology, though neither are exclusive to VAG cars. And when I say VAG cars, I also mean  Porsche, Bentley, Bugatti, Lamborghini and Ducati. Toyota, Honda, Ford, Mercedes also has it, in fact, virtually all cars manufactured post 1996  have an EPC warning light. EPC is an acronym for Electronic Power Control, and its a  warning light that resides inside the instrument cluster display.

EPC Light

Nonetheless, the EPC light is not all doom and gloom. It is there for a reason, and that reason is to safeguard the car and the engine from damage or destruction, especially considering what they cost to repair these days, let alone the cost to have an engine overhauled. Many people are under the misapprehension that the EPC light indicates an issue  with the cars  computerized system, whereas mechanics tend to echo that the EPC light indicates  a potential engine malfunction, though that's not strictly true either.  

MIL 

Before we continue, I just needed to add that when the engine malfunctions, it illuminates the Malfunction Indicator Lamp (MIL) aka Check engine light (CEL), which is indicative of  a computerized engine-management system malfunction. It even has an amber/orange icon of an engine, so as to draw your attention to the engine. Furthermore if this amber icon engine light is steadily illuminated, it indicates a minor engine fault but when it blinks it signifies a major engine fault. On the other hand, the EPC (Electronic Power Control) warning light  is a distinctly separate light from the MIL or CEL because it is related to a different function.

The more appropriate answer to 'What is an EPC light?' would be that the Electronic Power Control warning light, indicates a malfunction in your VW, Audi, SKODA or SEAT's  throttle control system, though once again that's also not totally accurate either.  So let me throw so light on the subject. The EPC light is in fact a diagnostic test light. So when the car's ignition is first switched on, the EPC light is illuminated for about three seconds. If there are no faults in the EPC system the light will automatically extinguish.

Drive by Wire

This three second time period is the duration of a self-diagnostic test. Effectively the Motronic ECM (J220) checks for malfunctions  in the Electronic Power Control (Torque system) accelerator system (drive-by-wire system), which includes the Throttle Body Drive Stepless Motor (G186) with its dual   independent Throttle Drive Angle Potentiometers (G187 & G188), the Accelerator Pedal Module with its dual independent Throttle Position Sensing Potentiometers (G79 &G185), the wiring harnesses that connects them all together and its associated sensor inputs from the Cruise Control  System, the Anti-lock Brake System (ABS), the Oxygen Sensor Control, the Automatic Transmission and the Air Conditioning System, etc. 

Charge Air Path

Here Air conditioning system mean all components involved in conditioning the air in the inlet manifold prior to combustion, implying the Throttle body / Mass Air Flow (MAF) sensor G70 and not A/C as in HVAC.  That being said, the functionality of an Electronic Throttle Control (drive-by-wire system) can regulate the Charge Air Path far more accurately than a physical cable between the accelerator pedal and the throttle valve. 

NonVolatile Memory

This being the case, by the time the EPC light illuminates on the dashboard  in response to some sensor detecting a problem  whilst driving, the problem already occurred.  The  EPC warning is just a way to tell you that there  was a glitch in the EPC (drive by wire system) and generally remains lit until the fault is cleared. The EPC light is known as K132 and is turned on by the Motronic ECM by providing the Ground  connection that keeps the light burning. At the same time, a DTC is registered and stored in non-volatile memory for later inspection.

Limp Mode

So the key piece of equipment to solving any EPC problem or issue is a diagnostic scanner. The fault below shows that the brake light switch F was the culprit that caused the EPC fault. Bearing in mind, that the Cruise control get its cancellation signal from the brake light when the brake pedal is depressed. When a brake light is fused or the dual contact brake switch goes open circuit and can't provide the requisite signal, the cruise control cannot be cancelled. The ECM detects this condition and construes it as a safety issue and sends the car into limp mode. 

Fault Codes

Essentially the EPC circuit prevented an accident from happening. Implying the brakes would work but the engine would still run at high rev set by the cruise control, meaning the brakes would be ineffective to bring the car to a stop. For safety reasons the EPC system closes the throttle valve to a predetermined position the brake pedal and the accelerator pedal are depressed simultaneously. However if the ECU detects that the brake was depressed before the accelerator, then acceleration will be carried out. 

1 Fault Found:
16955 - Brake Switch (F) 
P0571 - 35-10 - Implausible Signal - Intermittent

The fault below shows  that there is  an electrical malfunction in the Drive by Wire  circuit causing the EPC light to illuminate. After clearing the fault code, the EPC light just comes back on. The ECU was suspected and replaced but didn't solved the problem. It turned out that the  wiring harness between the ECU and the instrument cluster.

1 Fault Found:
18084 - EPC Warning Lamp (K132) Circuit: Electrical Malfunction 
P1676 - 35-00 - - 

The fault below  was on an Audi where signal from the Transmission  Control Module (TCM)  to the ECU was intermittent causing her to go into limp mode and idle really rough. Turned out that the TCM got wet from rain water that leaked into the carpets.  

1 Fault Found:
18265 - Load Signal: Error Message from ECU 
P1857 - 35-10 - - - Intermittent

VW electrical issues

VW Electrial issues

As we all know, Volkswagen, Audi, Seat and Skoda have several mechanical and electronic components in common, among which are their wiring looms with their huge variety of connectors. These connectors range from as few as 1 or 2 contacts per plug, to as many as 16, however the ECU and TCU edge connectors can range anything from for 32 to 68 pins,  up to 80 pins and even beyond. 

AUDI, VW, Skoda and Seat 2 pin connectors P/N535972721 - P/N1J0973772

Most modern cars have numerous control modules, for example the ECM (engine Control Module), the TCM (transmission Control Module), ABS Module (Anti-lock Braking System), Air bag Module, Convenience Module, Steering Control Module, Radio Module, Central  Electronics Module, Instrument module, CAN Gateway Module to mention just a few. Bearing in mind some cars have as many as 40 modules or more on board. 

TCU, ECU and Air bag plugs showing the multiple pin contacts.

Some of these modules control the sound system, the telephone system, the satellite navigation system, xenon ballast module, fan control module, suspension height control system, traction control system among so many others. Each of these modules and systems have numerous connector terminals / pins, some for its primary power, some for standby power, some for data communications, some for sensor inputs, some for actuator output, some for future expansion, some to accommodate different models  and probably some just for show. Each of these modules can have just a few contact terminals / pins whereas others can have close to 100 contact pins.

Molex ECU and TCU interface connectors that are normally
soldered onto the Printed Circuit Boards

When this glut of electrical contact terminals / pins / connectors are compared to those  of a pre-1994 vehicles, you shouldn't be surprised to see that they increased by at least a 100 fold. Meaning if your car of the 90's had as few as 200 electrical connections throughout the entire car, then its 2017 version would have 2000 electrical connections bumper to bumper. This is just a poor estimate for the sake of clarity but in reality their are way more connections. Pessimistically speaking that implies there are an extra 1800 connections that could go awry at any time, especially whilst driving in peak hour traffic or on a deserted road. Some of these 1800 connections include those for the EPC circuit, the throttle body, the check engine light, the crank sensor etc, and some many others that can be the cause that your car breaks down at the road side, leaving you stranded when you need the car most.

Female terminals seem to be the most troublesome of all connectors.

Since all cars are subject a certain amount of vibration that permeates throughout the body of the car, wiring looms and their connections are vibrating along with the engine, or bouncing and shaking along due to poor road surfaces. The car's body also flexes as it drives and the wiring harness flexes right along with it. Most of the VW plastic plugs and connectors have a locking system to keep them together, to prevent them from becoming adrift  whilst driving. But if there is excessive movement in the plug itself that causes contact friction, these contacts are not going to survive very long. The funny thing is, that we see this happening on a daily basis. Then there is chaffing of the loom against the car's body in places where goes through the firewall and the A and post.

The DLC 16 pin connector and a 12 pin connector with their crimp-on terminal pins

Most mornings on my way to work I see at least three rollback tow trucks either in the process of loading a VW or I see the rollback driving in the opposite direction of my travel or I end up over-taking  a rollback with a VW on its back.

So by just looking at the female terminal pins of all the images above, one can clearly see that all of them sport a tweezer like female tension receptacle that squeezes the male pin when it is inserted. Each of these female contact terminals have two little wings that secure them inside its plastic plug but when the terminal  goes intermittent contact it need to be replaced with one of the VW replacement wire kits displayed above.  

VW wiring harness connector terminal removal tool.

The "VW Wiring Harness Connector Terminal Removal Tool" below is used for this purpose, ie to release the terminal pin from its plug. Alternatively you can make your own tool with a paper clip. Straighten the paper clip then hammer both ends flat, then bent it in half to form a staple, so that the two flats are parallel to one another. The hammered flat edges can then be inserted on either side of the terminal pin  so as to push the terminal's wings back onto itself, making it easy to pullout.  Look at the image below. VW 2 pin coolant plug seems to be a favourite that goes wonky and needs replacement. Audi throttle body connector is another. VW, Audi 6 pin accelerator pedal plug is another troublesome connector. But that's best left for another post.

Cross section of terminal plug thats been cut open, see how the two wings in 
the top image is pushed flat by the harness connector tool in the lower image.

Volkswagen Electrical Problems

Volkswagen Electrical Problems

Electrical problems will invariably affect each and every new Volkswagen vehicle on the road today.  Generally, electrical problems are relatively easy to trace and repair, if you know what you doing, but it can be a nightmare when the faults present themselves as intermittent, especially considering cars have now gone CAN Bus, LIN Bus, Byteflight, MOST, Flexray, Zigbee, etc. VW EPC problems tend to be seriously intermittent, making every VW with an EPC issue a real bitch to diagnose.  Of late, more and more VW cars seem to be having EPC trouble among other bizarre electrical problems and very surprisingly, the VW service centers seem unable to repair them. 

Virtually everyone I know who has had an EPC issue, had to take their cars for repairs at least three to four times for exactly the same fault.  There are also numerous VW, SEAT, SKODA and Audi owners, who spent enormous amounts of money on replacement of "EPC issue causing components", yet the EPC faults remain. Essentially they lost money but I normally say they didn't loose money but bought experience and they paid dearly for it. Then there are others who are still waiting on the VW service agents / or some mechanic for their EPC problems to be solved after several months, a year and in some cases even longer.  

There was a time when virtually every electrical issue or loom (wiring harness) problem was associated  with the  FIAT brand. People even ascribed a nomenclature to FIAT - "First In All Troubles". However, it seems like Volkswagen  subsequently bought that patent, and now owns all right to it.

Electrical problems have never been as common place as they are today.

Let me give you an example, the wiring harness between the alternator and  the a  high voltage fuse box mounted on the battery of the VW Beetle has a tendency to melt or it just start to burn. It's a very well known problem and is also really common. It the  main reason that so many Beetles have burnt to a crisp. The Beetle wiring harness running between turn signals / headlights and the ECM is also troublesome -intermittent. The wiring harness resistance between the injector and the ECM changes over time from 1 ohm to above 30 ohms. The wiring harness resistance between the alternator and the battery also increases due to failing fans thus causing excessive current draw resulting in the wiring harness  over heating then melt.

I've seen VW Polo and VW Passt headlight wiring harness melt. The connectors tend to melt due to the type of plastic used and can be traced back to either arcing / overheating of the the bulbs or shorting out of deteriorated wiring. VW Passat coil pack wiring harness also prevents the car from starting and when water enters the wiring harness in the cowl area beneath the windshield,  it caused a short that normally damaged / corrodes the electronic control module. 

Both the Volkswagen CC and the Golf Mk5 GTI now seem to have throttle body wiring harness issues causing the EPC light to switch on and make the car go into limp mode. But there is no fault code that tells you the wiring harness is faulty or intermittent. Another VW CC harness problem to be on the lookout for, is the trunk lid harness that physically breaks over time  due to opening and closing of the trunk. A common problem on VW Pasat is the ignition wires that breaks inside its insulation, resulting in misfires.  VW sells a six pin throttle body sensor connector kit with yellow wires (below) that needs to be spliced onto the wiring harness to circumvent EPC issues when presented with wiring harness / G187 & G188 DTC errors.

Throttle body rewiring kit

Audi throttle body connector kit.  The wires kinda looks like single mode optical fibre cables along with  fusion splice protection sleeves

VW also sells a  six pin accelerator pedal  connector (below) that needs to be replaced as a solution to EPC problems when presented with wiring harness and G79 & G185 DTC errors. There is a likelyhood that this culture of poor quality wiring harnesses has spilled over into all the other VW models as well. To make matters worse, the newest mania among vehicle makers like Honda, Subaru and Toyota  for example,  are to use eco-friendly soy-based insulation wire for their engine wiring harnesses. VW's, Audi and Porsche, uses a soy based wire sheath to encase the engine harness. 

The six pin throttle pedal connector the goes intermittent causing EPC problems.

As a result, rats and squirrels are attracted by the aroma of the wiring harness and nibbles off the tasty insulation causing the bare wires to short out. Apparently these soy-based wire coverings are totally irresistible to rodents. As proof to this, several VW owners who have had electrical problems with their cars have vacuumed rats nests along with dog food chunk from their engine compartments. Others have removed several hands full of hazel nuts shells from their air filter boxes  that squirrels made their haven.  

Replacement six pin connectors for VW Audi SEAT and SKODA

Be that as it may, modern day car soy based car components are not a first, during World War II, some U.S. states used soybean fiberboard for their license plates, which proved extremely popular among goats that made a feast out of them. All I can say is, that VW service centers are going to make a small killing by replacing wiring harnesses of the millions of VW on the road today. Personally, I think you whole biodegradable "go green thing" , "eco this eco that" is overrated and is  getting out of hand. 

Some time back, some Dummkopf  -Dr. Dieter Zetsche- at Mercedes Benz decided that all Mercedes Benz cars manufactured during 1992 – 1996 should be fitted with biodegradable wiring. This leap toward eco friendliness by Mercedes Benz was well-intended but those wiring harness prematurely disintegrated due to engine heat and caused untold electrical problems. VW should in fact take a lesson out of the Mercedes Benz's annals.

See the cracks and the brittleness of the wire insulation after just a few ears of use

However, there is a DIY remedy for biodegradable, rodent enticing soy flavoured wiring harnesses.  Honda Acura Acura supplies a genuine-OEM rodent-deterrent duct tape, which is treated with capsaicin, - super-spicy red-hot chili pepper compound - that deters rodent.  Wrapping you VW wiring harness before rats discover your car is the way to go. Enough said, so let me return the subject at hand. 

Spicy anti rodent insulation tape,

In the not too distant past, Volkswagen Jetta models manufactured between  January of  2005 and January  of 2006 were sold with a "defective door wiring harnesses". It wasn't that the harness was defectives in the sense of not working but rather the harness was made too short. As a result, thousands of Jetta owners were experiencing similar problems as the harness started to chafe and disintegrate through regular use.

Common experiences included loss of power to the door controls, failure of the power window controls, failure of the power mirror controls, failure of the fuel tank latch release, failure of the boot lid release. Other weird experience included loss of audio to the speakers, a tripped air bag light on dashboard, when locking the door with the key fob remote the radio to turn on, or the key fobs just doesn't work, also having to recharged the battery continually because it runs down overnight. The interior door-open lights wouldn't turn off  and neither would the buzzer, the sunroof opened randomly. The turn signal in the side mirror stopped flashing and neither would the hooter work but would beep at odd times when you least expect it.  The windshield wipers worked occasionally and the car alarm would trigger unexpectedly and repeatedly.

In fact most VW Jetta owners complained about loss of some or all of the controls located on the driver's door.  These  faults weren't confined to the driver's door, because it was purely a matter of time before the the passenger door also developed a short or an open circuit in  one or more of its electrical circuit. The only way to remedy the problem was to replace the  broken harness with a genuine VW replacement which turned out to be some 80 mm longer than those fitted in the Jettas doors.

VW Jetta Front door replacement harness

A class action suit was leveled against Volkswagen alleging that they knew the door wiring harnesses were deliberately  made too short at the time these Jettas were sold. It was further alleged that Volkswagen shortened the harness by 80mm was  so that they could save costs, which  would ultimately lead to premature breaking of the door wiring harnesses boosting replacement harness sales.

However, most other Volkswagens electrical problems can possibly be traced back to a a troublesome ground. Water somehow enters the ground wires, in the cowling below the windscreen traveling inside the wire insulation resulting in corrosion. Always check the ground connections located  under the battery tray, or ground connections underneath the air cleaner box, or located inside the windshield wiper cowling or in the engine compartment, or the ground connections on the steering column or behind instrument cluster.   Covering the ground connections with battery terminal grease should offset the corrosion, if any, Remember poor ground connections, can cause a multitude of problems if it they become loose, can cause anything from cam sensor codes, to instrument cluster problems like erratic speedometer display, to misbehaving fuel gauge, to a dead gear indicator light, to non operational windshield wiper,  to a flickering digital clock , etc. 

Volkswagens that are equipped with air conditioning  are subject to high ambient temperatures which often causes the battery to get drained whenever the radiator fan kicks in at full speed with the ignition shut off.  Under high heat conditions, the gas pressure of the refrigerant can activate the A/C high pressure switch, triggering the high speed radiator fan relay to activate the cooling fan. Volkswagen has subsequently recommended a replacement fan relay switch with other minor modification of the A/C high pressure switch wiring, to solve this problem.

Replacement Radiator fan control switch

Whenever your VW misbehaves and you cannot put your finger on it, the best thing to  do is to investigate every ground lug on every bit of the engine wiring harness that you can get at. Loosen it, cleaned it with a  wire brush and some emery cloth and if needs be replace ground lugs that are corroded and possible even the screw/ nut. Don't forget to retorque the nut to the requisite tension. It may even be beneficial to add a second heavy duty ground strap to decrease resistance if any. Heavy duty welding cable from a welders supply store is far more  tolerant to vibration than your average cheap jumper cable wire. Starting difficulties can often be traced / associated to a poor ground connection. 

Remember when repairing wiring harnesses that soldering is not the recommended nor the appropriate method of repairing  it.  Solder joints are not flexible and tend to break after  while due to vibration.  Always use insulated crimp lugs and bullets like these below on connecting terminals especially at ground distribution points.

Lugs, bullet and spade connectors for repairing ground connections.

There is a tendency among car manufacturers to  miniaturize the physical size of electrical connector contacts and thereby the oversize of the connector. The problem is that the surface area of contact is remarkably reduced and are thus prone to intermittent contact under vibration. This has now become very evident on the wiring loom connectors that interface with the throttle body and the accelerator pedal to the point that they need to be replaced when they go intermittent. Don't bother to spray them with contact spray, just replace them. they are cheap enough to buy rather than suffer constant EPC issues and they are even available on Amazon, ebay, DHgate, and other online auction.

@DomLittlewood I need your help on a case I have with Volkswagen. A Brand new Volkswagen Polo numerous electrical problems & now caught fire

— Deano Luke (@95deanluke) August 30, 2016