Audi Workshop Service and Repair Manuals

In the adaption process, the engine control unit learns various throttle valve positions with the ignition switched on and the engine stopped. These positions are stored in the control unit. Feedback on the position of the throttle valve is provided by the two throttle valve drive angle senders.

Adaption must always be performed if the throttle valve control part -J338 or engine control unit is removed and installed/replaced or if the engine control unit power supply is interrupted.

Adaption is implemented:

• ◆ By initiating basic setting function (04), display group 60 with ignition on.
• ◆ Automatically if ignition is switched on for at least approx. 6 seconds without actuating starter and accelerator pedal and engine control unit recognises that "learning is required" (it is however not possible to see whether or not adaption has been performed successfully). "Learning required" is recognised if stored voltage values from the angle senders do not coincide with currently measured voltage values within a certain tolerance range.

Test requirements

• ● No faults stored in fault memory , Interrogating fault memory
• ● Accelerator pedal not pressed
• ● Coolant temperature greater than 5°C but less than 100°C
• ● Intake-air temperature greater than 5°C
• ● Supply voltage for engine control unit greater than 11 V; checking
  
• ● Connect vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "address word" 01 => Page 01-8.

• ‒ Press keys 0 and 4 for "Start basic setting" function and confirm entry with Q key.

• ‒ Press keys 0, 6 and 0 for "Display group number 60" and confirm entry with Q key.

After pressing Q key, throttle valve actuator is initially de-energised.

In this condition, the throttle valve is pulled into an emergency running position by a mechanical spring in the throttle valve control part. The values supplied by the two angle senders in this emergency running position are stored by the engine control unit.

The throttle valve is then opened a certain amount. Once this value is attained, the throttle valve actuator is de-energised again. The mechanical spring then has to close the throttle valve within a certain period to the previously learnt emergency running position (spring test).

The throttle valve is then closed by the throttle valve actuator; the values provided by the angle senders in the throttle valve control part are stored in the engine control unit.

De-energisation of the throttle valve actuator by the engine control unit whilst driving becomes apparent in the form of a higher uneven idling speed. Acceleration is only transmitted to the engine after a long delay.

• ‒ Check specification for throttle valve control part (display zone 3).

• ‒ Check specification for throttle valve control part (display zone 4).

Note:

Termination of adaption process by control unit may be due to the following:

• ◆ Throttle valve cannot be completely closed (e.g. dirty)
• ◆ Battery voltage too low
• ◆ Fault in throttle valve control part or wiring
• ◆ Engine started during adaption process or accelerator pedal pressed
• ◆ Throttle valve housing strained (check bolted joint)

Following termination, tester displays "Function unknown or cannot be implemented at present". Adaption is restarted automatically when ignition is next switched on (several seconds).

• ‒ Conclude basic setting of engine by pressing⇒ key.
• ‒ Press keys 0 and 6 for "End data transfer" function and confirm entry with Q key.