VAG

VW DIY

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

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

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

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

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

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

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

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

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

POWER CONTROL

ELECTRONIC POWER CONTROL EXPLAINED

As I mentioned in a previous, blog German Automotive Technology is really, really cool. German car design and automotive technology is currently at the forefront of going green, with the result that all other motor manufacturers are turning green with envy. Pardon the pun. German car design technology doesn't flaunt the colour green as eco-friendly but rather blue. 

Mercedes is pushing Blue Efficiency as their future technology and VW is flaunting Bluemotion as their new technology.  Polo de Volkswagen Bluemotion technology started out with the 2007 Polo (not my 2007 Polo Classic) and may be seen in some of their new vehicles. It's futuristic in the sense that it saves fuel. It saves all the fuel that would have been used, if the car was allowed to idle. Blue Efficiency and Bluemotion fuel technology doesn't allow the car's engine to idle, so when you start the car, it doesn't actually idle but the dashboard lights indicate that the engine has started. Logically there is no engine noise since there are no revs. The moment the car is engaged into gear and you remove your foot from the brake pedal, the engine starts instantly and pulls away as if it has been idling all the time. Exactly the same happens when coming to a compete stop at a traffic light or stop street. The engine switches off when the car comes to a halt, and remains off whiles you foot keeps the brake pedal depressed. However, the moment the pedal is released, the engine starts and the car moves off as if the engine was never switched off. There is no delay.

Having  said that, can you contemplate or just imagine the complexity of the electronics, both hardware and software employed in Bluemotion Technology, considering that many of the service agents are even stymied by the current German technology used in cars prior to 2008. The EPC on Volkswagen, Audi, Skoda, is just one of them. Central locking is another, ABS is a third and airbag a fourth. Intermittent reverse light whilst driving a fifth, brake light is on, blowing brake light fuses is a sixth and the list goes on. The repair and service charges for the non-Blue motion vehicles are already over the top so what can we expect to pay for repairs to Bluemotion technology vehicles. Besides who is going to repair them? Currently service agents are trowing spare parts at each electronic problem hoping that it would solve the problem but in most cases doesn't solve the problem.

Anyway, it appears that quite a few visitors who viewed my Electronic Power Control - EPC solution blog have no idea what a potentiometer (sender)  is, so let me explain and use the VW Polo accelerator pedal [accelerator position sensor (G79 & G185)] as a basis for understanding. Below is a picture of a potentiometer marked "A" that may be used in an electronic circuit. It specific one could be used as a volume control in an amplifier, or a sensitivity control on a disco strobe or a brightness control for a lamp dimmer. The uses for potentiometers are endless and has been used in cars for quite some time.

An overview of the  Electronic Power Control Circuit - EPC  in Volkswagen, Audi, Skoda.

The accelerator sender marked B and the throttle body housing marked C as seen above each have a gang potentiometer (meaning more than one potemtiometer in the same housing)  VW calls these both these potentiometers senders since they provide input to the ECU - Engine control Unit.  The ECU controls  the Drive-by-wire and any problems with it causes the car to go into "Limp Mode" resulting in the EPC warning light or other dashboard lights to come  on. Have a look at Electronic Power as to how the entire accelerator throttle  circuit is controlled and interfaces with the OBD2 /OBD II and Can Bus network.