Audi Workshop Service and Repair Manuals

The adaption process enables the engine control unit to learn the various positions of the throttle valve 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 actuator angle senders.

An adaption must always be performed if the throttle valve control part (J338) or the engine control unit is removed and refitted or replaced, or if the voltage supply to the engine control unit is interrupted.

The learning process (adaption process) is performed:

• ◆ By initiating the basic setting (Function 04) of display group 60 with ignition switched on.
• ◆ Automatically if the ignition is switched on once for at least 6 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 requirement is recognised if stored voltage values from the angle senders do not coincide with current measured voltage values in a certain tolerance band.

Note:

Engine will not start during automatic adaption.

Test conditions

• ● No fault stored in fault memory
  , Interrogating fault memory
• ● Engine stopped, ignition switched on.
• ● Accelerator not depressed.
• ● Coolant temperature at least 5 °C but below 100 °C (display group 4, display zone 3).
• ● Intake air temperature at least 100 °C (display group 4, display zone 4).
• ● Voltage supply to engine control unit greater than 11 V, testing .

• ‒ Connect the vehicle diagnostic, testing and information system VAS 5051 or fault reader V.A.G 1551 and select the engine electronics control unit with "address word" 01 => Page 01-8.
  For this purpose, the ignition must be switched on.

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

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

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

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 part. 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 senders in the throttle valve control part 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 specification for throttle valve control part (display zone 4).

Note:

The deciding factor is not how the learning stage counter (display zone 3) behaves during the adaption process, but that specification in display zone 4 "ADP OK" has been attained after adaption.

"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).
• ◆ Connectors (e.g. on throttle valve control part) have become loose, are not properly engaged or contacts in plugs are corroded/bent.
• ◆ The battery voltage is too low.
• ◆ Throttle valve control part or wiring is defective.
• ◆ Engine was started or accelerator was actuated during the adaption process.
• ◆ Distortion of throttle valve housing (check screw connection; tightening torque: 10 Nm)

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.
• ‒ Press keys 0 and 6 for the function "End data transfer" and confirm entry with the Q key.