Audi Workshop Service and Repair Manuals

The adaption process enables the engine control unit to learn the various positions of the throttle valve control unit with the ignition switched on and the engine not running. these positions are stored in the control unit. The feedback signal indicating the position of the throttle valve comes from the two throttle valve drive angle senders.

If the throttle valve unit -J338 or the engine control unit are remove and installed or replaced or if the voltage supply from the engine control unit is interrupted an adaption must always be performed.

The learning process (adaption process) is performed:

• ◆ Automatically if the ignition is switched on once for at least 10 seconds without actuating the starter or the accelerator pedal and the engine control unit recognises "Learning requirement". In this case, however, it is not obvious whether the adaption process was successful or not. Learning demand is recognised if stored voltage values from the angle senders do not coincide with current measured voltage values in a certain tolerance band.
• ◆ By initiating the basic setting (Function 04) of display group 060 with ignition switched on.

Note:

Engine will not start during automatic adaption.

Special tools and workshop equipment required

• ◆ VAS 5051 with VAS 5051/1

or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Preconditions:

• ● No fault recorded in fault memory, interrogate fault memory .
• ● Engine stopped, ignition switched on.
• ● Accelerator pedal not depressed.
• ● Coolant temperature 10...95 °C.
• ● Intake air temperature 10...90 °C.
• ● Voltage supply to engine control unit greater than 12.7 V, Testing .

Procedure

• ‒ 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
  For this purpose, the ignition must be switched on.

• ‒ Enter "04" to select "Start basic setting" and confirm with Q key.

• ‒ Enter "060" for "display group number 060" and confirm entry with Q key.

After the Q key is pressed, the throttle valve actuator is first disconnected from the electricity supply.

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

The throttle valve is then opened by a predetermined amount. When this value is reached, the throttle valve actuator is again disconnected from the electricity supply. The mechanical spring should then close the throttle valve to the previously learnt emergency running position within a specified period of time (spring test).

The throttle valve actuator then closes the throttle valve; the values supplied by the angle sensors in the throttle valve control unit are stored in the engine control unit.

If the engine control unit disconnects the throttle valve actuator from the electricity supply while the vehicle is being driven, the result will be an increased and fluctuating idling speed and a very poor throttle response.

• ‒ Check specified values for throttle valve control unit in display zones 3 and 4.

Note:

"ADP" in display zone 4 stands for "Adaption".

Note:

If the adaption is interrupted by the control unit, the reason could be one of the following:

• ◆ The throttle valve cannot close completely (e.g. dirt).
• ◆ The battery voltage is too low.
• ◆ Throttle valve control unit or wiring is defective.
• ◆ Engine was started or accelerator was actuated during the adaption process.
• ◆ Distortion of throttle valve housing (check screw connection).

When adaption process is interrupted, message "Function is unknown or cannot be carried out at the moment" is displayed on tester. The next time the ignition is switched on (for several seconds), the adaption process is automatically performed again.

• ‒ End the engine basic setting by pressing the ⇒ key.