Showing posts with label Electronic Throttle Control. Show all posts
Showing posts with label Electronic Throttle Control. Show all posts

Monday, April 24, 2017

NO PROBLEM FOUND

NO PROBLEM FOUND

Have you ever taken your under warranty car to your service agent after experiencing extreme EPC Light and Engine Light activity, only to be told "No problem found"? Does the inside of your under 75,000km  car sound like an aviary when you turn-on it's fan? Or, do you constantly have to top-up your oil level between oil changes or at least every 1500 km? How do you handle it, when you go to the agents, to complain about excessive oil consumption, only to be  told that, “all cars use oil and oil consumption is a normal part of a car’s operation, beside oil consumption issues were disclosed in the vehicle owner’s manual". Has your car behaved like a washing machine during a rinse and spin cycle while driving on the freeway, misfiring, shaking and scaring the living day light out of you? If yes to any of the above, then you must be driving a VAG Car - VW, Skoda, Audi or Seat. Yes, when those injector coils go faulty in mid travel, it really frightens you because the car feels like is going to fall apart any moment.  

This also happens to VW, Jetta, VW Caddy, Volkswagen Jetta, Volkswagen Golf, Volkswagen Beetle, Volkswagen Passat, Volkswagen Touareg, Porsche Cayenne, Volkswagen Amarok, Volkswagen Caddy, Volkswagen CC,  Volkswagen Fox, Volkswagen Gol G5,   Volkswagen Golf Mk6,  Volkswagen Jetta, Volkswagen Scirocco,  Volkswagen Sharan, Volkswagen Tiguan, Volkswagen Touareg,   Volkswagen Touran, Audi A3, Audi A6, Audi A7, Audi A8, Audi Q5, Audi Q7, Volkswagen Phaeton, Volkswagen Polo, Volkswagen  Lupo and Volkswagen Passat.

I've experienced the radiator fan blades disintegrate while driving, and the unbalanced rotation caused the same, exact, identical, engine shake. Then I've also experienced starting difficulties, irregular idling, poor fuel economy, hesitant acceleration, engine misfires and engine stalls. Not to mention the the constant, "in your face" red engine  warning light. All of which turned out to be components of the charge air path, especially the Mass Airflow Sensor (MAF).

When the "No problem Found" response became unbearable, it was time for self discovery. So what I've come to realize is that a mass air flow sensor, is integral part of every modern VAG engine and is normally situated somewhere inside the intake air duct, between the air filter and the engine. 

I've owned several cars, amongst which were Renault, Opel, Mercedes Benz and Mazda yet never ever had the need to replace a MAF even after several years. However with VW, it needs to be cleaned or replaced regularly every 2-3 years. Cleaning a MAF is cheaper than replacing it though replacing a MAF sensor is just easier. It is DIY job because the MAF replacement cost at a VW dealers averages about R1500,00. 

MASS AIRFLOW SENSOR 


VAG engines require a "perfect blend" of air and fuel for absolute combustion. This "perfect blend" is known as stoichiometric or Lambda = 1, which essentially means "the mixture is right" in mechanical jargon. The vacumn caused by the turbo blower and the pistons down-ward travel creates air charge. The main aim of the charge air path is to provide a smooth increase in torque, and to deliver high efficiency throughout its  operating ranges. This air charge is measured by the MAF, so by implication a  properly functioning MAF is absolutely crucial to a smooth ride. But in modern Engine Management Systems their are several components that contribute to maintaining this "perfect blend" among which are:-

1) The Electronic throttle control (EPC)
2) Charge air pressure sensor G31
3) Mass Air Flow (MAF) sensor G70
4) Barometric Pressure (BARO) sensor F96
5) Intake Air Temperature (IAT) sensor G42 / G299

So any fault in the Mass Air Flow (MAF) sensor G70 will trigger the EPC light, because the Motronic engine control unit (ECU)  uses it as an engine load signal and as a reference data to calculate the  signal plausibility of other sensor inputs, when and how much fuel to deliver, and when to generate a spark for the relieve cylinder. At the same time, it will also trigger a DTC in memory. The MAF also works in conjunction with an O2 sensor that provides a “closed-loop” feedback  known as short term fuel trim (STFT) / Long term fuel trim (LTFT), in order to make corrections to that predicted air mass. If the air filter isn't replaced on a regular basis, a build- up of impurities in the MAF will cause it to start failing when it gets too dirty to do its job and trigger the EPC light. 


Thursday, June 11, 2015

AUDI EPC LIGHT PROBLEMS


AUDI EPC LIGHT

It is common knowledge that EPC light problems have been haunting Audi drivers incessantly for the past few years, announcing itself on Audi A1,  Audi A2, Audi A3,  Audi A4,  Audi A5, Audi A6,  Audi A7,  Audi A8,  Audi Q3,  Audi Q5, Audi Q7, the Audi RS4,  Audi RS6, Audi RS8, Audi R8, Audi S4, Audi S6, Audi S8 and Audi  TTs even before they're run-in. Several Audi owners are dismayed that EPC problems present themselves on virtually new cars. 

In fact, EPC problems pop-up at any time, on any Audi new or old fitted with X-by-Wire technology. Any Audi  without a throttle cable, is naturally fitted with a full Drive-by-Wire system which is supervised by the Electronic Control Circuit (EPC)  / Electronic Throttle Control (ETC)  that turns on the dashboard mounted EPC (K132) indicator light when it detects a malfunction, then registers Diagnostic Trouble Codes (DTC)  in the ECM memory.  Even though the EPC light turns on exclusively for  non-emission related faults, it does however turn on along with the MIL for emission related faults. 

The EPC  / ETC is a torque monitoring circuit and monitors for torque discrepancies and torque inefficiencies and when it detects one, sends the vehicle into emergency running mode (limp mode). These are prevalent when towing, when driving up an incline, when in manual mode, when in cruise control, after spirited driving, etc, and may even cause the ABS, ESP   lights to came on. Some drivers, assume  that it's happening more frequently over time and others are concerned that the EPC trouble are going to get worse because of its  randomness. But this is not the case. 

Bear in mind that once the EPC light is on, no other EPC related fault is going to make it glow any brighter. Once it's on, it's stays on even if the battery is disconnected, and it will come back on when you reconnect. However, the ECU will monitor the EPC circuit and if the same error does not occur in three successive trips of at least 7 kilometers, it will erase the DTC and it would seem as if it never happened, until the next time.  These are safely features specific to Drive by Wire systems and their workings can be viewed in the adaptation groups when retrieving errors with a scan tool.

ADAPTATION GROUPS PERTAINING TO EPC

Group 60 -- Throttle Valve Adjuster / Adaptation Epc-system
Group 61 -- Epc-system / Throttle Valve Adjuster (System 1) 
Group 62 -- Epc-system / Throttle Valve Adjuster (System 2)
Group 63 -- Kickdown Function
Group 66 -- Cruise Control Status

AUDI EPC LIGHT RELATED DTC

18039 / P1631 - Accelerator Position Sensor (G79): Signal too High 
18041 / P1633 - Accelerator Position Sensor 2 (G185) Signal too Low
18042 / P1634 - Accelerator Position Sensor 2 (G185): Signal too High
18047 / P1639 - Accelerator Position Sensor 1/2 (G79/G185): Implausible Signal 
 00777 - Accelerator Position Sensor (G79): Implausible Signal

No response from the throttle even with your foot flat on the accelerator pedal.. There are two potentiometers fitted to the accelerator pedal which are monitored by the ECU and when it it detects an intermittent signal from one pot, it turns on the EPC light then uses the second pot for acceleration but it is limited. When both pots detected as are intermittent, EPC light goes on and engine only runs at idle speed. When this error occurs, turn the engine off, stomp on the accelerator a few times through its full travel.  It could just be specks of dust that settled on the one of the potentiometer (variable resistors) tracks that stymied the ECU for a few millisecond or so. I this happens often and thereafter, presenting a 18047 / P1639 or 18039 / P1631 or 18042 / P1634 or 18041 / P1633 then consider replacing the accelerator pedal.

No response from the throttle even with your foot flat on the accelerator pedal. There are also two redundant potentiometers in the throttle body that determines the throttle valve angle and it has three modes of failure. One for when the valve angle sensor fails, one for when throttle valve actuator (motor) malfunctions and one for when throttle valve position is cannot be recognized by the ECU. When this happens  the ECU shuts off the voltage supply to the actuator, causing the throttle valve to defaults to mechanical stop position and the engine speed is limited to 1200 RPM. If any of the DTC fault below show up in your scan, check the 6 pin plug interfacing with the throttle bodyIt would be best to redo adaptation thereafter before thinking of replacing the throttle body. 

000289 / P0121- Throttle Position Sensor (G69): Implausible Signal - Intermittent
16506 / P0122 - Throttle Position Sensor (G69): Signal too Low - Intermittent
17987 / P1579 - Throttle Actuator (J338): Adaptation Not Started - Intermittent
17976 / P1568 - Throttle Actuator (J338): Mechanical Failure 
17972 / P1564 - Throttle Actuator (J338): Under-Voltage during Basic Setting 
17952 / P1544 - Angle Sensor 1 for Throttle Actuator (G187): Signal too Large - Intermittent
16606 / P0222 - Angle Sensor 2 for Throttle (G188): Signal Too Low - Intermittent
000547 / P0223 - Angle Sensor 2 for Throttle (G188):Signal Too High - Intermittent
17581 / P1173 -  Angle Sensor 2 for Throttle Actuator (G188) Signal too High 
18042 / P1634 - Accelerator Position Sensor 2 (G185): Signal too High 

You have difficulty starting but eventually does start but idles very rough, bucks and surges when you attempt to drive it. The   EPC, MIL (Check engine light)  and ESP lights come on. This is most likely caused by the Injectors  N30-N33 or the Ignition Coils N (1st cylinder), N128 (2nd cylinder), N158 (3rd cylinder) and N163 (4th cylinder) since both the Injectors and Ignition coils causes exactly the same symptoms. It also   exhibit the following DTCs.

17633 / P1225 - Fuel Injector for Cylinder 1 (N30): Short to Ground  - - Intermittent
17634 / P1226 - Fuel Injector for Cylinder 2 (N31): Short to Ground  - - Intermittent
17635 / P1227 - Fuel Injector for Cylinder 3 (N32): Short to Ground  - - Intermittent
17636 / P1228 - Fuel Injector for Cylinder 4 (N33): Short to Ground  - - Intermittent

MORE EPC PROBLEMS

J757 Engine Component Power Supply Relay cause loss of  high-pressure and turns on EPC. ESP and MIL lights.

N75 Solenoid valve for charge pressure limitation and turns on the  EPC and MIL lights but shown no symptoms of failure except go into limp mode. 


Audi A1, Audi A2, Audi A3, Audi A4, Audi A5, Audi A6, Audi A7, Audi A8, Audi Q3, Audi Q5, Audi Q7, the Audi RS4, Audi RS6, Audi RS8, Audi R8, Audi S4, Audi S6, Audi S8 and Audi  TTs EPC Problems.

Wednesday, January 9, 2013

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 PoloAudi 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 suchthe 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 2Accelerator 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

   
DON'T FORGET to VISIT

VW, SEAT SKODA and AUDI OWNERS  found the following sites interesting.  
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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...,