DRIVE BY WIRE

VW - DRIVE BY WIRE (Drive-by-Wire)

If you arrived on the VW Polo website because you searched for  Drive by Wire (DBW), EPC, or EPC light or engine won't rev, Steer-by-Wire, or limp mode,  then you have certainly arrived at the right place. There are several definitions for ECP, the first of which will be explained, is Electronic Parts Catalog (EPC).

EPC stands for Electronic Parts Catalogue (EPC) and all Audi, Volkswagen,  Skoda and SEAT parts are listed in ETKA V7.2 EPC (Electronic Parts Catalogue). This catalogue is purchasable online and downloadable but the file is huge. Companies like Mercedes Benz, Toyota,  Enigma, Attrakt among many, many others host computer based electronic catalogs of the individual auto parts and accessories that make up their engines, cars, tractors, specialized machinery and farming equipment etc. Restated, an EPC is a catalogue in electronic format much like CVS data or a database file or similar, that can be downloaded or is accessible online.

Then there is the second type of EPC - Electronic Parts Catalog (EPC) software. MultiCat and Msys.EPC are companies that specialize in the software that can display an exploded view of an assembled device. For example, the exploded view of an engine, or gearbox, or cylinder head, showing the individual bolts and nuts, flanges, hoses and brackets, etc. and their component part numbers.

Thirdly, there is also the Electronics Parts Catalog (EPC) which is an electronic list or database of semiconductor components, from diodes to transistors to integrated circuits to thyristors, etc... This EPC is often called and equivalents book or catalog and hosts the specifications of semiconductors from several manufacturers. A typical EPC is the RS Electronic Components and Tools Database. This EPC doubles up as the third type of EPC which is the Electronic Product Code. Component Product Codes look like,  1N4148 or BC337, MCP2515, TYN812RG, etc... for electronic components.

However, there are many more EPC definitions, some of them can be found at the end of this blog. I could explain all of them individually but none has any relevance to the subject at hand, viz EPC - Drive by Wire. Drive-by-Wire also know as  DbW, Steer-by-Wire "x-by-wire" or simply "by-wire".

DRIVE BY WIRE

And finally, the Electronic Power Control (EPC) that freaks out almost each and every VW 1.6 Polo, Audi TT, Skoda, SEAT and  Golf TDI, owner. Most vehicles with Drive by Wire [Drive-by-Wire (throttle control)] usually have a Electronic Power Control (EPC) indicator lights on its dashboard which lights up when  there's a problem with the Drive-by-Wire system. This would involve the two accelerator pedal sensors G79 and G185 and in some cases the two sensors G187, G188 inside throttle control valve body - control actuator. [As discussed in my previous blogs] When the engine idles, neither the Throttle Valve Angle Sensor nor the Accelerator Pedal Position Sensor are monitored for faults by the ECU, as such, the engine does not respond to accelerator input but will limit engine to 1200 RPM.

The  basic components that constitute the Electronic Power Control (EPC) circuit. 

There is no throttle cable involved, because its an electronic throttle control.

The Electronic Power Control (EPC) circuitry consists of EPC light, Accelerator Pedal, Throttle Control Valve,  DBW  (no throttle cable,) Injectors and the Engine Control Unit (ECU). Have a look at the diagram above. The inputs to the ECU is marked green and the outputs from the ECU is marked blue.  Check that the brake light bulbs are OK, if not check the brake fuses. There are other inputs to the ECU from numerous other sensors or units for example the Automatic Gearbox Control unit, Cruise control unit, Air conditioning unit, Lambda Regulation unit, Knock Sensor units, Alternator, Engine Speed Sensor unit, ABS and the  Power-assisted steering unit to mention but  a few. 

The CAN-Bus bidirectional connection is marked in orange. Some of the other inputs like Knock sensors and Lambda regulator and Engine Speed Sensor unit can also cause the EPC light to come on. If the Engine Speed Sensor unit is responsible, it will reset itself after a while and if the Lambda regulation is faulty the vehicle will smoke and turn on both MIL and EPC lights, but if the Drive-by-Wire - DBW (not drive by cable) system is faulty then only the EPC light will be on.

Both the accelerator sensors and the throttle valve sensors work on the same principle since all 4 of them are potentiometers. The input voltage is 5 Volts and the increments are in millivolts implying that there is an  acceleration range of between 0 and 5000.  Throttle valve angle  sensor 1 and Throttle valve angle sensor 2, Accelerator position sensor 1 and Accelerator position sensor 2 sliders makes contact with the resistive track and outputs the appropriate voltage level to the ECU. These resistive tracks are prone to go faulty since they are gold plated contacts running on gold plated copper tracks etched on a PCB. Over time the contacts wears right through the gold and copper plating, only making contact with the bakelite or fibreglass substrate. This type of potentiometers are less reliable than ceramic thick-film potentiometers.

When the EPC warning light goes on and your acceleration goes limp and the engine won't rev-up there is an easy cure but there may be exceptions. Get the car home even if it means driving really slowly in "Limp Mode". Once home, disconnect the battery for about 15 minutes or so, but not more than 20 minutes then reconnect. NB! do not disconnect the Live terminal, disconnect the Earth terminal. If the battery is disconnected for more than 20 mins you will lose your radio settings since the radio also participates in volatile and non-volatile memory of  the CAN-Bus. 

Reconnect the battery but make certain that the ignition is off. Once this is done, turn on the ignition so that the dashboard lights go on but do not start your car and DO NOT touch your accelerator pedal. After about 5 minutes the throttle body will aligns itself. After 10 minutes turn off the ignition, wait for 2 mins then start the car and let it idle for abut 2 minutes as well. By now, the EPC warning light should be off and the engine will rev as normal.You may have to to this twice. If this worked for you, please do give me some feedback with a comment.

VW Airbag diagnostics 

VW Instruments - Immobilizer

   

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COME MORE EPC DEFINITIONS

EPC - Engineering, Procurement & Contracting, 

EPC - Engineering, Plant  Construction,

EPC - European Paralympic Committee,

EPC - Electronic Product Code, 

EPC - Event Promotional Council,

EPC - Energy Performance Certificate,

EPC - Engineering, Procurement and Construction, 

EPC - Event-driven Process Chain, 

EPC - Evolved Packet Core,

EPC - European Patent Convention,

EPC - Eastern Provincial Council, 

EPC - Electronic Poetry Center, 

EPC - European Policy Centre,

EPC - European Political Community, 

EPC - European Political Cooperation, 

EPC - Evangelical Presbyterian Church 

EPC - Export Promotion Council, 

EPC - Electricity Plant Controller, 

EPC - ElectroPlating Cathode,

EPC - European Payments Council,

EPC - Electronic Packet Collision,

EPC - Electrical Professionals Council,

Etc...,

MANIFOLD

MANIFOLD / EXHAUST

It was about 2:30 a.m. when I returned from a long distance trip. I was tired but smiled to myself before I climbed into bed because my 2007 VW Polo Classic Highline really performed well and brought me home without incident. I was amazed, blown away in fact. 

After breakfast the following morning, I intended to go to Milnerton to see a client but when I started the VW Polo, I was greeted by  frighteningly loud noise. I smiled too soon. Immediately I switched off the engine. It actually sounded like the VW Polo had no manifold system fitted at all. For the record it wasn't like the sound of a broken silencer or a hole in the exhaust system. It literally sounded as if there wasn't any exhaust system at all.

My first thought was that someone must have liberated my exhaust system during the night whist I was asleep and sold it off as scrap metal. Theft in my locality has become quite rife and this is known to have happened. Radiators and batteries seem to be targeted more often.  However, on closer inspection I was relieved that the exhaust was still there. I started the VW Polo once more rolled underneath the front suspension and discovered hot air was blowing from a space  where the flange gasket is located. It was very awkward to get my hand in there and I was wondering what this repair was going to cost. A trip to "Mister Silencer" and three hundred and twenty bucks later the VW Polo was once again ready for the road. I expected one of the dashboard EPC warning lights to light-up or one of the CanBus interconnected computer modules to immobilize the car but its seems that the manifold exhaust  just runs much too hot to attach a sensor to it.

Anyway, in order to fix or fit a new flange gasket the complete knuckle had to be removed. They hoisted the car on a maintenance lift and inspected its underside for the origin of the noise. It came from above the flexible bend which looked like matted wire mesh. Essentially the joint between the manifold branch and the exhaust manifold had to be removed.  I was told the flexible mesh compensate for vibration, should the silencer knock against a pavement of something, it wouldn't brake off of get damaged because of its flexibility.

Just two days prior to this, a young women ran into my rear bumper with her sparkling new look Audi A8 whilst she was chatting on her cellphone. There was no physical damage to neither of the cars but thought that she was the cause that my exhaust had given trouble. According to the dude at "Mister Silencer", its highly unlikely because the impact from behind would not have pushed the exhaust towards the engine because of its flexibility. Oh well,  either way I had to pay for it. FYI my VW Polo had every service on time since new and currently has 88250 Km on the clock. Soon it will be going for its 90000 km service and my timing belt will be changed. I've been driving with the dreaded fear that it might snap in mid travel and bend all my valves in the process or even bust the tops of one or two pistons.

In my first blog I mentioned I simply love German engineering because when a German designed car snaps a timing belt, there is no mechanical damage to the engine. This is so unlike the Japanese, American, English and French designed cars, all of which bend valves, bend conrods, break pistons or knock holes through their cylinder block. Since my VW Polo Classic 2.0L Highline is soooo different from all the previous German cars I owned, I just have this feeling it was designed along the same money making monopolistic ideology of modern car design - the cash cow that  sells spare parts.

Dudes and Dudettes, if you found this blog informative or even remotely helpful, recommend it to others by clicking on g+1 below.