Programming and Relearning
Throttle Valve Control Module, Adaption
The adaptation process enables the engine control module to learn the different 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 angle sensors for throttle valve drive.
If the Throttle Valve Control Module -J338 or the engine control module is removed and installed or replaced, or if the power supply to the engine control module is interrupted, an adaptation must be performed.
The learning process (adaptation process) is carried out:
- By selecting "Basic Setting" (function 04), Display Group 60 with the ignition switched on.
- Automatically if the ignition is switched on for at least 6 seconds without operating the starter or depressing the accelerator, and if the engine control module registers a "learning requirement." (In this case, however, there is no way of knowing whether the adaptation process was successful or not.) The engine control module will register a learning requirement if the previously stored voltage readings from the angle sensors do not correspond (within a certain tolerance range) to the new voltage readings.
Test conditions for adaptation of throttle valve control module
- No malfunctions stored in DTC memory, check DTC memory.
- Accelerator pedal not depressed
- Coolant temperature between 5 °C and 105 °C
- Intake air temperature above 5 °C
- Voltage supply to engine control module more than 11 V, Testing.
- Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". When doing this the ignition must be switched on.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -4- to select function "Basic Setting" and confirm entry with -Q- button.
Indicated on display
Basic Setting
Input display group number XXX
- Press buttons -0-, -6- and -0- for Display Group 060 and confirm entry with -Q- button.
Indicated on display
System in Basic Setting 60 ->
1 2 3 4
When the -Q- button is pressed the throttle valve positioner will be switched mechanically.
In this condition the throttle valve is pulled into an "emergency running" or default position by a mechanical spring in the throttle valve control module. The values supplied by the two angle sensors for this emergency running position are stored in the engine control module.
The throttle valve is then opened by a predetermined amount. As soon as it reaches this position the current supply to the throttle valve positioner is again disconnected. The spring should then close the throttle valve mechanically to the previously learned default position within a specified period of time (spring test).
The throttle valve positioner then closes the throttle valve and 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 current supply to the throttle valve positioner while the vehicle is being driven, the result will be an increase in idling speed with fluctuating engine RPM (hunting) and very slow throttle response.
Display Group 060:
- Check display readout for throttle valve control module (display fields 3 and 4).
Display Group 060:
- Check display readout for throttle valve control module (display fields 3 and 4).
NOTE:
If the adaptation process is interrupted by the control module and the tester display indicates "Function is unknown or cannot be carded out at the moment" the cause could be one of the following:
- All test conditions must be met.
- The engine was started or the accelerator depressed during the adaptation process.
- The throttle valve is unable to close completely (e.g. because of dirt)
- 6-pin harness connector not properly to throttle valve control module connected.
- Wiring is faulty.
- Distortion of throttle valve housing (check bolts)
- Throttle valve control module faulty.
- End engine basic setting by pressing the -> button.
- Press buttons -0- and -6- to select "End Output" function and confirm input with -Q- button.