Sunday, May 22, 2016



This blog is a continuation of a previous blog named AUTEL D900 SCAN TOOL in which I outlined its indispensability and necessary tool to repair any VAG vehicle. Anyway, I hooked up the D900 2015 version to my polo classic 2.0l highline. As can be seen below, its software is already at version 15.7 and dated July 2015 meaning that it's a huge improvement compared to the 2011 model. There are 30 vehicle manufacturers  listed in the Autel 900 menu, the 28th of which is Volkswagen and the last selection is other, meaning any vehicle not listed. I did a DTC scan but there was none stored in memory. Neither was there any vehicle information nor freeze frame data. Compared to VCDS the live data is accurate. I was interested to see the coolant temperature increase while the car idled and that's exactly what I saw. 

The OBD2 monitors are abbreviated and I dropped in a list for ease of identification below. Unfortunately I can't demonstrate the DTC feature since there were not DTCs to display. I verified with my VCDS to make sure that the D900 isn't saying that there isn't any while there may be some.
Abreviations o the various OBD2 monitors.

In my opinion the D900 is good value for money. Initially  I was sceptical that it didn't support Polo but it clearly does. It supports Audi and Porsche but doesn't specifically list Skoda nor Seat.  It may read then under other but I will have to check this and this post later. A list of VAG cars that it supports can be seen here.

The D900 laying on the passenger seat.
The D900 switch on, first screen.
D900 supports Volkswagen and Audi 
D900 has 7 functions, 6 of which can be seen here

D900 reads MIL status, Freeze frame and I/M readiness

Live data from my VW polo 

More live date from my VW Polo

The following 3 pics are  self explanatory

More live data from my VW Polo

Tuesday, May 10, 2016



So, you have an electrical problem with one of your car's relays and you have no idea which one is troublesome or misbehaving because even the Bentley manual got that information wrong. Well, your'e in for a treat because I have listed several VAG relays in their "marking number order", making them easy to identify. For example, the manual lists the Motronic Engine Control Module Relay as item (J271) which is in fact Relay #428 for older gasoline powered VW, AUDI, SKODA and SEAT cars and Relay #460 for later (newer) gasoline powered VW, AUDI, SKODA and SEAT cars whereas  Relay #109 is the Motronic Engine Control Module Relay for older diesel powered VW, AUDI, SKODA and SEAT cars and Relay #120 for later (newer) diesel VW, AUDI, SKODA and SEAT cars. VAG cars have relays strew all over the car, sometimes in the engine compartment, sometimes under the dashboard, sometimes in the fuse distributor, etc, so they're not always that simple to find. However if you know what they do, then fault finding relay issues / problem,  becomes simple.

Relays with their VAG numbers inscribed on the plastic housing.


Technically, a  relay is just a remote switch. Most of the VAG relays are 4 pronged, and the reason relays are use as remotes switches, is because its contacts can carry a lot more current than a dashboard mounted switch. Besides relays make it convenient to switch several sets of contacts simultaneously when the solenoid in energized. Relays come in all sorts of configurations among which are single pole single throw, double pole double throw, etc and can be really toublesome. Most VAG solenoids have 4 prongs, 1 or 2 regular prongs used for the solenoid winding and 2 or 3 heavy duty prongs allocated for the switch contacts that carry higher currents. Relay contacts can become intermittent after suffering consistent contact bounce. The relay solenoid can even burn out, causing the relay not to respond. The most common problem on relays is cracked or dry solder joints on the printed circuit board around the heavy duty prongs. I've also found the plastic stays that supports the metal relay contact melt due to heat build-up rendering the mechanical switch movement inoperative.

Cracked / Dry Solder joints. This is what happens inside relays.

It is also common for relay contacts to fuse/melt/weld together either in the normally open or the normally closed position.  A telltale sign is that the plastic housing is discoloured in an area and often bulged due to excessive heat where this happens. Sometimes the relay prongs heat up so much that it melts  the socket it plugs into causing the PVC/plastic to flow between the prong and socket contacts causing an open circuit. Either way, relay will have to be replaced and perhaps even the relay socket.  VW used many Multi purpose relays like Relay #1, Relay #53, Relay #204, Relay #645 to mention but a few. These can easily be used in place of most other relays should it meet the necessary current specifications.  Spade terminals connected to a short lengths of appropriate thickness wire  from each sprong and plugged into the correct relay socket slot can serve as a converter if the switch prongs are differently configured from the one you need.

VAG Engine Control Module Relay Circuit showing  the relay output powering-up the ECU.

VW Relays, SKODA Relays, Audi Relays, SEAT Relays,

Relay #1 SEAT, VW Relay Multi Use Relay ... Part No - 171 906 383

Relay #7 AUDI Relay - ABS Hydraulic Pump Relay

Relay #13 VW, SKODA Relay - A/C Relay

Relay #15 AUDI VW SEAT SKODA glow plug relay  (same as #202) ... Part No - 8A0 951 253

Relay #17 SKODA, Audi Seat VW relay  ... Part No - 171 937 503A

Relay #18 VW, Audi, Seat, Skoda, Load Reduction Relay  ... Part No - 191 937 503

Relay #19 VW, Seat, Audi  Relay - Wiper Interval Relay ... Part No - 321 955 531A

Relay 20 VAG VW Audi Skoda Relay - Rear Window Wiper Relay ... Part No - 171 955 529

Relay #21 Polo Passat, Bora, Caddy, Emergency Signal Flasher Relay ... Part No - 191 953 227 A

Relay #22 VAG, VW, Audi, Skoda, Indicator Hazards Relay  ... Part No -  431 953 231

Relay #27 Seat Relay - Belt Warning Control Module Relay

Relay #30 VW, AUDI Relay - Rear Window Wiper/Washer Relay

Relay #31 VW, Audi, Seat, Wiper Timed Relay ... Part No -  191 955 532A

Relay #33 VW relay - Headlight Washer System Relay

Relay #36 VW, Audi, Seat,  Lights Left On Buzzer Relay ... Part No -  3A0 951 307

Relay #38 VW, Audi, Seat, Skoda,  Air Conditioning Relay  ... Part No -  191 906 383A

Relay #53 VW, Audi, Seat, Skoda Relay -  Multi Use Relay ... Part No -  141 951 253B

Relay #67 VW Jetta relay - FP (Fuel Pump) Relay

Relay #68  VAG,VW, Audi,Skoda, Coasting Relay (Fog lights / Horn)... Part No -  811 919 098B

Relay #72  VW, Audi, Seat, Rear Wiper Relay ... Part No -  191 955 529

Relay #74  VAG, Control Unit Fuel Cut Off Relay ... Part No - 811 919 096G

Relay #76  VW, Audi Relay -   Double Relay ... Part No - 443927826,

Relay #79 VW Relay - Remote Rear Lid Relay

Relay #80   VW,  12v 40 Amp Fuel Pump Relay ... Part No - 191 906 383

Relay #87 VW AUDI Relay - ABS Relay

Relay #88  VW, Audi, Seat Relay - Buzzer Relay ... Part No - 443 951 307ABC

Relay #94  VW  Audi Relay - Head light Relay ... Part No - 191 906 383B

Relay #99 VW Relay - Washer/Wiper Intermittent Relay

Relay 100  Jetta, VW, Polo, Golf Relay -  SAI relay (secodary Air Injection)   (J299)

Relay #100 VW, Audi , Seat, Skoda, Golf , Bora  Beetle, Load Reduce Relay 7M0 951 253A

Relay #109  ECU Power Supply Diesel AUDI, Skoda, Seat, VW,  ... Part No - 357 906 381A

Relay #117 VW Audi Seat  Control Unit Relay Part Number 357906121

Realy #120  VW AUDI VW Diesel Engine Control module relay ...  Part No - 1H0 906 123

Relay #128  VW AUDI  Headlight Control Relay Part 7M0 941 597

Relay #131 VW Audi Seat Skoda  Timed Cooling Fan Relay Part No 357959485

Relay #134 Audi, VW,  Diesel Engine Relay Part No - 357906123

Relay #147  VW Audi Seat  Air Conditioning Relay Part No 1H0959142

Relay #149 VW Audi Seat Skoda  Rear ELECTRIC OPENING VENT WINDOW Nr 357959485

Relay #151  VW Audi Seat Skoda  Rear Fog Light Realy Part Number191945383

Relay #153 VW Audi Seat Skoda PNEUMATIC IDLE SPEED BOOST Part No357907467

Relay #167  VWAudi Seat Skoda Fuel Pump Relay With Part No 191906383C

Relay #168 VW, Audi, Aircon Retardation Relay Part No 7M0906363

Relay #169 VW Audi Seat Skoda Relay Heated Rear Window Relay Part No 7M0959627C

Relay #136  AUDI , VW GOLF, IBIZA 1.9 AAZ Engine Control Unit Relay 1H0 906 123 A

Relay #185 VW, Audi,Seat, Skoda, Relay For Starter Check Part No - 3B0 91 1251

Relay #200  VW Audi Seat Skoda Relay Part No. - 7M0 951 255

Realy #201 VW Audi Seat Skoda Relay Close Contact Relay Part  No. - 443 951 253T

Relay #202   AUDI A4/A6 VW PASSAT Relay  - Glow Plug Relay NO 202 8A0 951 253

Relay #203 VW Audi Seat Skoda GLOW PLUG RELAY FUEL PUMP Part No 8A0 951 253A

Relay #204  VW, Audi,   Skoda, SEAT Relay - Multi Use Relay Part Number 4319 512 53H

Relay #205 VW Audi SEAT Relay - Contact Close Relay Part Number 443 951 253

Relay #206 VWAudi Seat Skoda Relay For Air Con Part Number 431951253F

Relay #208 VW Relay - Contact Close Relay Part Number 8A0951253B

Relay #213  VW Audi Relay - Coolant Fan Relay 443951253J

Relay #214  Audi, VW  Relay - Cooling Fan Muli UseRelay  443951253K / 8D0951253A

Relay #215 Audi Contact Close Relay Part Number No - 4439 512 53l

Relay #216  VW Audi Seat  Relay - Contact Close Relay Part Number 443 951 253M

Relay #217 VW Audi Relay Part Number 443 951 253S

Relay #218 VW Audi Seat Skoda  Window Regulator Relay Part No 895951254

Relay #213  VW Audi   SEAT Skoda Relay - Cooling Fan Relay  443951253J Relief a4 a6 a8

Relay #219 VW PASSAT  AUDI A4, TOUAREG Relay - 12V FAN RELAY 443 951 253 AA

Relay #229  VW Audi Seat Skoda Relay - Intermediate Wiper Relay Part No 431 955 531

Relay # 236 Audi Time Control Relay Part Number 443955532A

Relay #239 VW Audi Seat Realy - Rear Wiper Washer Relay Part Number 445955529A

Relay #240 VW Audi Oil Pressure Relay Part Number 443919082

Relay #241  VW Audi Oil Pressure Relay Part Number 443919082B

Relay #259 VW Audi Seat Buzzer Relay Part Number 443951307A

Relay #267 VW Audi Skoda Magnetic Clutch Relay 443919578C

Relay #272 VWAudi Time Control Relay Part Number 443955532C

Relay #297 VW Audi Control Unit GearShift Lock Relay PartNumber 443927351B

Relay #296 VW Audi Seat Skoda  Relay For Magnetic Coupling PartNo 443919578G

Relay #301 VWAUDI SEAT RELAY Part No 4A09194714A

Relay #305 VW Audi Seat Skoda AC Compressor Control Unit Relay No 443919578J

Relay #310 Audi Relay - Oil Pressure Relay Part Number 893 919 082A

Relay #337 VW Audi Seat Skoda Relay Part No 4A0 907 413

Relay #339 VW Audi Seat Skoda Relay For ABS Part No 4A0 907 517

Relay #342 VW AUDI Audi Air Conditioning Clutch Relay Part No - 4A0919579C

Relay #351 VW Audi Seat Skoda Relay For ABS Part No 4A0907513A

Relay #355 VW Audi Seat Skoda  Relay PartNo 4A0 907 413A

Relay #357 VW Audi Skoda  Seat Cruise Control Relay... Part No - 4A0907307A

Relay #361 VW, AUDI, SEAT 1.9 TDI Relay   ... Part No - 4A0 907 440

Relay #364 Audi Seat Skoda VW Relay Part No 4A0951258

Relay #366 VW Audi Seat Skoda Relay Part No 4A0907413B

Relay #368 Audi Seat Skoda VW Relay For Heater Unit Part No 4A0 907 045

Relay # 370  VW Audi Relay Close Contact Relay 8d0 951 253

Relay #373  AUDI VW Part Number: 8D0951253A (8D0 951 253A)

Relay #377  VW Golf   Bora  Intermittent Wash Wipe, fuse Relay ... Part No - 4B0 955 531A

Relay #381 VW, Audi, Skoda, Fog Light Relay ... Part No - 431951253G

Relay #387 VW, Audi, Skoda, Head light Brake Warning Relay ... Part No - 4B0 919 417

Relay #389 VW Relay - Headlight washers Relay

Relay #390 VW, Audi, Multi Function Steering Wheel Relay ... Part No - 4B0 907 487

Relay #399  VW, AUDI,  Audi A8,  Multi Function Steering Wheel Controller

Relay #410 VW, Golf  MK4,  Lupo, Bora, Pasat, VW Polo Relay - Fuel Pump Relay 6N0 906 383A

Relay #411 VW, Passat, Jetta, Golf, Skoda , Seat, Relay ... Part No - 1J0 959 485 A

Relay #428 VW, Audi, Motronic Engine Control Module Relay (J271)  

Relay #430  VW Audi, Seat, Skoda, Relay   ... Part No -7M3 959 143

Relay #433 VW Golf, Touareg Relay - Starter Cut Off Relay, ... Part No -  3D0 951 253 A

Relay #451 VW GOLF BORA Relay - Multi Function Steering Wheel Relay control Unit  1J0 907 487A

Relay #460  VW GOLF JETTA Relay - Passat Engine Control Unit Relay ... Part No - 1K0951253A

Relay #461 VW Touran Relay - 1T2 1.9 TDI (J271)  Glow plug Relay  03G 907 282A  

Relay #460 ECU Relay,  VW GOLF MK5 JETTA Passat Audi A3 TT 1K0951253A

Relay #645 Audi VW Skoda Seat Relay - Multipurpose  Cooling Fan Relay 4H0 951 253A

Sunday, May 8, 2016



The supermini SEAT Cordoba based on the Seat Ibiza Mk2, has been around since 1993. When the Volkswagen AG took over production from the Spanish auto maker, it was  replaced by the Ibiza ST /  Seat Vario built on the same platform as the Mk4 VW Polo and the Skoda Fabia. They are available in coupe, saloon and estate in 1.2, 1.4,  1.6, 1.8 and 2.0L petrol and 1.9L diesel engines with either a 5-speed manual or 6-speed tiptronic gearbox, and were in production until 2009. These cars  were  renown  for their good performance, handling and its safety features, but like all cars, they tend to develop common problems after a few years. Pero es un buen coche para comenzar en Mexico y EspaƱa.

The most common of all engine problems was engine misfiring and in the process turning on the Seat check engine light, or the Seat Ibiza engine warning light, or  Seat Altea engine warning light, or the Seat Leon engine warning light, or Seat Arosa engine warning light, or Seat Leon TDI engine warning light, or Seat Cordoba  engine warning light. The most likely cause of this problem was the coil pack or the spark plug leads which needs replacement. A telltale sign was excessive  shaking when idling. This was very prevalent when coming to a stop street or traffic light or when starting first thing in the morning. Unlike cars of yesteryear  that had a single coil and a distributor that supplied a spark to the upcoming spark plug; these cars have its own coil pack for each cylinder. More coils packs  just increased the amount of things that could go wrong, and do they go wrong.

Another common problem with the Mk4 was a lack of power which also turns on the Seat Ibiza engine diagnosis warning light or Seat Cordoba engine warning light.  The cause of the problem in most cases is  the MAF (mass air flow) sensor. A telltale sign is a lack of power at high speeds and or just  poor overall acceleration. It is always worthwhile to try and clean it with compressed air but if this didn't solve the problem, replacement is the only option.  Once repaired,  one would feel an immediate improvement on performance. 

Many Seat Cordoba window wipers also just suddenly stops working which sometimes turned out to be the wiper linkage that seized and sometimes turns out to be the wiper motor and sometimes both. Then there is the ever creaking noise sometimes sounding like an exhaust rattle coming from the front suspension when driving over speed bumps or rough surfaces. This turned out to be the anti roll bar bushes which after replacement solved the problem. A problem that plagued the automatic models is the ever noticeable red oil mark on the ground underneath the car. The origin of the leak is either gearbox seal leaking or the selector shaft seal that is leaking. Seal replacement normally stops the leak. Failure to address this problem ends up with the gear lever stuck in park with the PRDN light glowing right red on the dashboard. The gearbox  grinds when attempting to put the car into drive but will kick in with an huge thud.

Then there is the breaking distance problem on certain models (Ibiza, Toledo, Cordoba, Leon, Vario and Inca) fitted with ABS, needing a lot more force to be applied to the brake pedal to get the car to stop. The cause of the problem turned out to be tension cracks that develop in the vacuum pipe going to the brake servo near to the connections area. This is in fact a manufacturing fault that can be replaced under recall free of charge. After replacement of the vacuum pipes breaking was back to normal.

Ibiza, Altea Toledo, Leon Toloedo, Cordoba  and Alhambra vehicles fitted with a 3 and 4 cylinder pump injector engine with 2 valves per injector is prone to the bolts on the tandem pump cover that breaking off.  This was also a manufacturer  fault and vehicles were recalled to have the pump checked that was supplied by a certain manufacture.

Seat Ibiza and Seat Toledo and Seat Leon with VINs ranging from VSSZZZ1MZ1B036908 to VSSZZZ1Mz1B044227 seem to have a problem with head airbag unit which would fail to activate under certain collision conditions. Seat Altes,Toledo and Leon with 2 L TDI engine and  6 speed manual VIN ranging from VSSZZZ5PZ4R000048 to VSSZZZ5PZ4R017390 and VSSZZZ5PZ5R000026 to VSSZZZ5PZ5R103620 and VSSZZZ5PZ6R000009 to VSSZZZ5PZ6R001638  have flywheel problems that was also recalled for replacement.

The Seat Cordoba 1.9 TDI also developed starting problem when not driven for a day or two. But will eventually start after several attempts, idling very rough and smoking. In some cases it just drained the battery as well. But once she started it will start every time thereafter until left to stand for a day or two again.  This was caused by the diesel pipes sucking in air causing the diesel to flow pack towards the tank. The cause was a leaking diesel filter. A very annoying problem with some Mk4 is the drafts that comes in through door seals. It seemed that these rubber seals tend to collapsed after 5 years. Another thing is the coolant sensors / temperature sensors are generally of a very poor quality on all VW/Audi/Seat/Skoda group cars. They just tend to go faulty all the time. Surprisingly most of these problems are also prevalent in VW Polo range, after all SEAT is just another Mk4 VW Polo that has been badge engineered.

Thursday, April 28, 2016



In the German language, Volkswagen means "The People's Car". However, the People as a whole are energetically rejecting Volkswagen cars in favour of other brands of automobiles. Volkswagen (VW) as a company has suffered  tremendous financial losses and has fallen from grace because of the cheating devices that gave rise to the emissions scandal that affected 11 Million vehicle globally. The cheating German auto manufacturer, recently announced a EUR4.1 Billion euros (USD4.6 Billion) operating loss for the year 2015 and set aside an additional sum of EUR16.2 Billion (USD18.2 Billion) to pay for its diesel emissions test-rigging scandal. But regardless of the amount of money Volkswagen is throwing at the problem,  the VW share price had already plummeted from US$244.30 in early April 2015 to US$166.98 by mid September 2015. This 32% decline in share price slipped  even further by a whopping 18.5% to close at USD 136.15 by of third week April 2016. So within one year and two  weeks the Volkswagen share price fell by a massive 44.3% in  value. 

Volkswagen's USD 18.2 Billion shlush fund is destined to cover the costs of legal expenses, penalties, claims, recalls and vehicle buy back from all the countries affected by the diesel emissions cheat software, essentially to cover all cost incurred last year. Somehow this  US$18.2 billion  is likely to be just the beginning of their woes because on Thursday 21 April 2016, a US federal judge announced that Volkswagen promised the  US government that they will buy back as many as 482,000 diesel cars, as well as pay all penalties to make up for the  pollution generated by their cars.

Having said that, it's been a very bad week for German automakers as a whole because a US attorney seizing an opportunity to make hoards of money, has sued Daimler over Mercedes Benz's diesel pollution. He hired a company to test Mercedes-brand diesels driving on real roads, the findings showed that they spewed out much more nitrogen oxide virtually all the time than the amount stated. He shared the test results with California regulators which will surely trigger an inquiry  by the US Environmental Protection Agency, into Daimler Benz's emission figures. He also intimated that there could also be some complicity on the part of European governments. Daimler said the lawsuit’s claims are totally without merit and that the investigation is unrelated to the VW emission scandal. The company also repeatedly denied  using emission defeat devices or manipulating emissions tests. 

However Daimler AG did concede that the US Department of Justice asked the company to investigate irregularities in diesel emissions in its Mercedes brand vehicles. Now that at least two German automakers are under US scrutiny, the emissions-cheating witch-hunt could be growing exponentially. Senior Kelley Blue Book  analyst Karl Brauer said that  Mercedes Benz, Volkswagen and other automakers, and several governments have known for years that diesel cars only met with emissions standards in the lab, but not on real roads. He also added that it was so understood, even if not documented; essentially an agreement between the automakers and the European governments. Hardly had the above transpired when Germany’s transport minister announced that five automakers agreed to recall 630,000 diesel vehicles in Europe following an investigation into emissions levels. Recalls include Mercedes and Opel, as well as Volkswagen and its subsidiaries Audi and Porsche.

Earlier this year, Dutch emission tests revealed that a Mercedes C-Class BlueTec diesel emits 40 times more nitrogen oxide on road tests than in lab tests. In other tests released by the British government during this week, have shown that diesels from Daimler and other automakers, including Ford Motor Company, Nissan Motor Company and Hyundai Motor Company, perform vastly differently in lab tests than they do on the road.

Volkswagen, the German carmaker Volkswagen announced on Friday past (April 22) that the massive engine-rigging scandal it is currently engulfed in, pushed it into an annual loss, for the first for more than 20 years, but the final total costs are still incalculable.

Back in Tokyo Japan the latest fuel consumption misconduct is at play. Mitsubishi is embroiled in a fuel-consumption scandal affecting thousands of its vehicles and admitted to 'cheating' since 1991. They have been using an improper fuel-efficiency testing method for the past 25 years and have no idea how many cars are affected sold overseas that exceed the already known figure of 600 00 vehicles. Mitsubishi admitted that a group of unnamed employees rigged fuel consumption tests back in 2002 to make some of its cars seem more fuel-efficient than they actually were.   
A decade ago Mitsubishi  was pulled back from the brink of bankruptcy when it was found to have covered up a series of vehicle defects. But today Mitsubishi plans on  compensating customers in a bid to limit the fallout from the scandal. Meanwhile Transport ministry authorities raided Mitsubishi's  offices earlier in April.  

Mitsubishi Motors Corp’s president Tetsuro Aikawa bows with other company executives
at a news conference. Photograph: Toru Hanai/Reuters

These embarrassing global scandals have raised questions about the Japanese and German carmakers future, but points to a broader problem in the global car industry as regulators probe other automakers' pollution and fuel-efficiency standards. While the echos of these announcements are  is still resonating in the ears of the motor industry,  Germany's transport minister Alexander Dobrindt said  Volkswagen's emissions-rigging scandal sparked a inquest and found irregularities at 16 car brands, amongst which are Mercedes, France's Renault, Alfa Romeo, Chevrolet, Hyundai, Jaguar, and Nissan.

Tuesday, April 19, 2016



VW, Audi, Skoda and SEAT vehicles are crammed with wonderous technology, ranging from various electronic modules that overseas their general functionality to hoards of sensors that monitor how these vehicles behave and actuators that respond to software controlled decision making elements. One could say that collectively they give cars a degree of Artificial Intelligence and their seamless integration makes motoring a lot easier. But when something goes wrong, there is also a swarm of warning lights on the instrument cluster that will flash at you until you take corrective action. However, knowing exactly what each warning light flashing on its dashboard is trying to tell you, is a completely different story. Even though some of these light are self explanatory and fairly obvious to understand, others are not, and  can be interpreted by looking in the owner’s manual. Knowing what these warning lights mean is really important to drivers because they can preempt a potential breakdown or full-on engine failure, insulating you from expensive repair bills.

As a general rule, warning lights illuminated either red or amber (yellow /orange), though a blue light is often used to indicate high beam and green lights are used to mean indicate left and right  turn signals. On a VW Polo a red warning light emphatically means that something needs to be done immediately. For example, the Oil pressure warning light, or the low brake fluid level light, or the parking brake warning light, or the Coolant level low / coolant temperature high light, illuminates red or flashes red as a danger sign and needs immediate attention. Failure to remedy can result in the engine seizing, the brakes failing, damaging your rear disks and brake pads, or the engine overheating resulting in a possible blown head gasket or worse, respectively. On different model VAG vehicles, the use of red and amber light may overlap. 

An amber / yellow /orange light  on the other hand serves to be rather informative and draws the driver]s attention to a potential problem or a problems that needs to be remedied soonest. For example the amber Anti-lock braking system (ABS) light, or the amber Airbag light, or the amber Immobilizer light, or the Brake pad wear light, or the Engine fault Onboard diagnosis (OBD) light, none of which will impede driveability nor endanger the driver. But this isn't strictly true especially when encountering the dreaded yellow EPC light


EPC stands for Electronic Power Control and has  much to do with controlling the electronic throttle hence it is sometimes referred to as the "Electronic Pedal Control". Probably because the throttle valve is actuated by an electric motor rather than a physical cable between the accelerator pedal and the throttle control valve. In essence the engine control unit responds to the sensor on the accelerator pedal and sends a corresponding command to the throttle valve positioner via four wires which is commonly known as "Drive by wire". But the EPC is much more than just an Electronic Pedal Control. Any malfunctions in the either the "Drive by Wire" circuit  or its associated sensors are detected by self-diagnosis and indicated by the EPC warning light.

The Electronic Power Control (EPC) is a circuit made up of various engine components or sub circuits that collectively addresses torque. In reality it should have been called "Electronic Torque Control". Should  a problem arise in the torque system, it correspondingly illuminates the easily identifiable yellow/amber/orange word "EPC" in the instrument panel.  The EPC circuit's decision making elements are embedded into the ECU which is responsible for the electric throttle valve positioning and overall torque-oriented engine management.

As such the ECU has to gathers all torque demand inputs in order to correctly calculate the appropriate control actions. These inputs includes, the Engine speed, the Engine load signal fetched from the air mass meter, the Vehicle speed, the shift point of an automatic gearbox, whether or not the air conditioner compressor is ON or OFF, whether or not the the cruise control system is engaged, whether or not the Traction Control System is engaged  or the braking  system is applied.

The combination Brake light / brake pedal switch provides a braking input to the ECU, failure of the switch to send data of the drivers foot on the brake pedal can trigger the EPC light in certain VAG vehicles, but definitely on the VW Polo. Don't be fooled by the brake lights that are working, when the brake pedal is depressed because it does not imply that the brake pedal switch is functioning as it should. In similar fashion the Clutch Pedal Switch provides cruise control input to the ECU, engaging the clutch, automatically disengages the cruise control which could also trigger an EPC episode.

This EPC light will come on when there is a problem:-

1) With either of the accelerator pedal senders.
2) With either of the throttle angle senders.
3) With the throttle valve control unit
4) With the accelerator / throttle harness.
5) With the throttle adaptation.
6) With grime and carbon build-up in the throttle body. 
7) If the the Throttle Valve Control Unit is replaced.
8) With the Brake Light Switch
9) With one of the Knock Sensors.
10 With the Mass Air Meter (MAF).
11) with the Engine control unit
12) With the Ignition system
13) With the Fuel injection system
14) With the ABS
15) With the Power-assisted steering system
16) With Lambda regulation (fuel consumption signal)
17) With the Alternator
18) With the TCM

Bearing in mind the throttle valve control unit is located on the intake manifold and needs to ensure that the engine is supplied with the appropriate and proper air flow. By implication the MAF measures the air flow and should there be a problem with it, the  ECU will not be able to calculate the proper torque and possible go into EPC mode. The consolation is that every fault that occurs would normally create a DTC entry. So the best way to determine the cause of the EPC light coming on, associated with loss of power and limp mode, is to do a diagnostic scan. 

Links to other EPC Problems!
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Sunday, April 3, 2016



In a matter of just a few short days, I've received a flurry of assistance requests from several VW owners,  all of whom seem to have power steering issues of some sort or the other. These issues ranging from complete failure of power steering to intermittent steering assist, to stiff and hard to steer. Among  the vehicles affected are VW Jettas,  Volkswagen transporters, Volkswagen Passats,  VW MKIV  TDI's and Golf Mk5s. Unfortunately specifics about steering problem can vary tremendously because some VAG vehicles are Hydraulically controlled, whereas some are electronic and others are ally controlled, all of which use slightly different technologies and components often spacely dissimilar.   

This implies some vehicles will have a Power steering pump as part of the steering rack assembly whereas others will have a power steering motor / hydraulic fluid reservoir a good meter separated from the steering rack. The following is  a general overview of the operation of VAG power steering systems. But what all these systems have in common, is the dreaded yellow steering light on the instrument panel which lights up for a 3- 4 seconds when the ignition is switched on but goes out after the engine is started. This is part of the self test that checks all electronic modules and mechanical mechanisms are synchronised to work together in harmony. However when the Servotronic warning lamp K92 stays on after the engine is started, there is definitely a fault with the power steering system.

When this happens it is a good idea to book the car in for repairs or do the repairs yourself because it could be quite  expensive.  Either way get the vehicle off the public road because loss of steering while driving can be very dangerous if not fatal especially going around corners because of the possibility of over steer.  An electro-hydraulic power steering system is fairly intricate because its control modules are interconnected. The Power steering control module controls the hydraulic pump motor which produces the hydraulic pressure needed for the steering servo assistance. But in order to this, it needs signals from the 'Powers steering sensor' which is located in the steering column and from the speedometer sensor via the 'Instrument cluster control Module' which is responsible for turning on the yellow steering wheel symbol should there be a problem. And lastly the Power steering controller also needs the engine speed data from the 'Motronic control Unit'. It also needs a 12V supply from terminal 30 as well as 12 volts supply from terminal 15 and of course an earth connection. The power wires are fairly thick and chunky which implies high current delivery. Poor electrical connection can cause arching which will disrupt functionality. Loss of any of signals or voltages to the Power Steering control module for even a few seconds will interrupt steering assist and make the car hard to steer. 

In a previous blog I described the  steering loss I encountered due to loss of  voltage to my car's hydraulic pump motor because my positive battery terminal was loose which resulted in intermittent supply to the main steering control module. It is worthwhile to  to check the level of the Hydraulic fluid in the reservoir when you suffer hard of stiff steering. If there is a leak, the hydraulic pump motor cannot produce the necessary pressure resulting in stiff steering. If the fluid is low, refill the reservoir but don't start the engine but get someone to continually turn the steering wheel between the left and right extremes while waiting for all air bubbles to surface. When the appearance of air bubbles  ceases, it would be ok to start the engine. It is also worth your while to   check for DTC's with a scan tool. Should there be a steering error,  deleting often restores steering assist. The LenkhilfeTRW V270 used in the Polo 9N is normally coded as 10110 which can be changed to 10120, 10130 or 10140 in order to incrementally increase the stiffness of the steering. For more Steering codings click here.

Friday, March 4, 2016



The modern day car in its current incarnation has increasingly become more and more electrotechnical than mechanical and technological advancements are constantly on the incline.  It is therefore  quite appropriate to say that vehicle owners need to become electromechanical savvy. In my opinion, the way forward is to invest in a scan tool for your particular make and model car. Since most people are familiar with Cell Phones, Decoders, Set Top Boxes, PVR, DVR and Televisions with various menus, or computers, access points and routers  with various wizards, navigating a scan tool would be relatively easy. A scan tool is an indispensable device for modern car diagnostics and is a technological marvel that's going to save you time and money, but only if you are willing to embrace the technology. 

In a previous blog I discussed VCDS which I think is a really fantastic piece of software with its hardware interface combination specific to VAG vehicles. The amount of Onboard information that is accessible with VCDS is astounding and it is literally beter than the factory  VAS Scan Tool used by VW /AUDI /SKODA / SEAT agents. In fact, in some cases VCDS  will even retrieve more faults than the VAS tools.  Be that as it may, as fantastic as VCDS is, it has major shortcomings for vehicle owners in general. Since VCDS is VAG specific, all other vehicle owners are at a loss to its technical capabilities and would have to look at other scan tools from  companies like  Auto Boss, Launch X431, Autel Maxidas DS708, Pro-Link iQ,  Mentor Touch ET6500, OTC Pegisys, Craftsman - 20899, G-Scan Oceania, Bosch 3824, etc, who produce commercial multivehicle scan tools. These companies cater for the automotive service industry since their scan tools are quite pricey and far beyond the budget of the average car owner.  If VCDS was multivehicle, it would be as good if not better than most commercial scan tools. However, since this is not the case,  Autel has come to their aid of the average car owner. Autel has a low cost handheld scan tool that is multivehicle compatible that supports the following list of vehicles.

Acura, Audi, BMW, Buick, Cadillac, Chevrolet, Chrysler, Daewoo, Dodge, Eagle, Ford, Geo, GMC, Honda, Hummer, Hyundai, Infiniti, Isuzu, Jaguar, Jeep, Kia, Land Rover, Lexus, Lincoln, Mazda, Mercedes Benz, Mercury, Mitsubishi, Nissan, Oldsmobile, Pontiac, Porsche, Plymouth, Saab, Saturn, Scion, Suzuki, Toyota, Volkswagen, Volvo.  

I acquired the 2015 version because of its versatility because it supports several models of each of the above mentioned vehicles. I wanted it to diagnose my Renault but discovered that it unfortunately does't support Renault and even more surprisingly it doesn't support my  VW Polo  2.0L Highline (9N) either but it does support the the following list of VAG vehicles.

Audi A3
Audi A4
Audi A6
Audi A8
Audi A8L
Audi All road
Audi Cabriolet
Audi S4
Audi S6
Audi S8
Audi TT

Volkswagen Beetle
Volkswagen Bora
Volkswagen Eurovan L5
Volkswagen Eurovan VR6
Volkswagen Golf A3
Volkswagen Golf A4
Volkswagen GTI
Volkswagen Jetta A3
Volkswagen Jetta A4
Volkswagen Passat
Volkswagen Touareg

I don't know if the previous years version (Autel D900 2012) supports older vehicles like 2002-2010, but am of the opinion that all newer scan tools are backward compatible though I may be wrong. Anyway, the Autel scan tool is really cool, it comes with a mini CD containing a pdf file of all supported vehicles. I would have thought they would include a list of generic DTCs for Chassis / Powertrain (P-codes), Body (B-codes)  and Network (U-codes) for easy of identification. What this implies is that you will have to either find these lists online, save them as pdfs or print them or access the internet resources to identify the codes every time you car throws you a DTC.