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.

If the throttle valve unit -J338 or the engine control unit are removed, installed or replaced or if the voltage supply from the engine control unit is interrupted, 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 "adaption requirement". In this case, however, it is not obvious whether the adaption process was successful or not. Adaption requirement 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

Preconditions:

• ● No faults stored 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 => Page 01-3 and select vehicle system "01 -Engine electronics" in the selection. For this purpose, the ignition must be switched on.

→ Display on VAS 5051:

• ‒ Under -1- select the diagnostic function "04 - Basic setting".

→ Display on VAS 5051:

•     1 -    Enter display group
  max. input value = 255

• ‒ Enter "060" for "display group number 060" in zone -2- and confirm the entry by pressing the 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 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 learned 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 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.

→ Display on VAS 5051:

• ‒ Check specifications for throttle valve control part 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 part 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.

• ‒ Exit the function "04 - Basic setting" by pressing the ◂ key.