Programming and Relearning
Throttle valve control module, adaptation
The adaptation process enables the engine control module 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 module. The feedback signal indicating the position of the throttle valve comes from the two throttle valve drive angle sensors. An adaptation must always be performed if the throttle valve control module -J338- or the engine control module is removed and reinstalled or replaced, or if the voltage supply to the engine control module is interrupted.
The learning process (adaptation 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 module recognizes "adaptation requirement". In this case, however, it is not obvious whether the adaptation process was successful or not. Adaptation requirement is recognized if stored voltage values from the angle sensors do not coincide with current measured voltage values in a certain tolerance band.
Test conditions for adaptation of the throttle valve control module
- No DTC stored in DTC memory, Checking DTC memory
- Engine stopped, ignition switched on
- Accelerator not depressed Coolant temperature greater than 5 degrees C but less than 105 degrees C.
- Intake air temperature above 5 degree C
- Voltage supply to engine control module greater than 11 V, testing.
- Connect vehicle diagnostic, testing and information system VAS 5051 or V.A.G 1551 Scan Tool and select engine electronics control unit with "Address word" 01. For this purpose, ignition must be switched on.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press keys 0 and 4 for function "Introduction of basic setting" and confirm entry with Q key.
Indicated on display
Basic setting
Enter display group number XXX
- Press keys 0, 6 and 0 for "display group number 60" and confirm entry with Q key.
Indicated on display
System in basic setting 60 ->
1 2 3 4
After the Q key is pressed, the throttle drive is first disconnected from the electrical 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 module. The values supplied by the two angle sensors in this emergency running position are stored in the engine control module.
The throttle valve is then opened by a predetermined amount. When this value is reached, the throttle drive is again disconnected from the electrical supply. The mechanical spring should then close the throttle valve to the previously adapted emergency running position within a specified period of time (spring test).
The throttle drive then closes the throttle valve; the values supplied by the angle sensors in the throttle valve control module are stored in the engine control module.
If the engine control module disconnects the throttle drive from the electrical 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 value for throttle valve control module (display zones 3 and 4).
Display Group 60:
- Check specified value for throttle valve control module (display zones 3 and 4).
Display Group 60:
NOTE: If the adaptation process is interrupted by the control module and the tester display indicates "Function is unknown or cannot be carried out at the moment" the cause could be one of the following:
- All test conditions may not have been met
- Engine was started or accelerator was actuated during the adaptation process
- The throttle valve cannot close completely (e.g. dirt)
- Connector (6-pin connector) at throttle valve control module not engaged
- Wiring connections faulty
- Distortion of throttle valve housing (check screw connection)
- The throttle valve control module is faulty
- End engine basic setting by pressing key.
- Press keys 0 and 6 for function "End data transfer" and confirm entry with Q key.