Programming and Relearning
Throttle Valve Control Module, Adaptation
The adaptation process enables the Engine Control Module (ECM) 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 ECM is removed and installed or replaced, or if the voltage (power) supply to the ECM is interrupted, an adaptation must be carried out.
The learning process (adaptation process) is carried out:
- By selecting "Basic Setting" (function 04), Display Group 060 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 (ECM) 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.
NOTE: The engine will not start during automatic adaptation.
Test conditions for adaptation of throttle valve control module
- No malfunctions stored in DTC memory, check DTC memory
- Engine not running, ignition switched on
- Accelerator pedal not depressed
- Coolant temperature between 5 °C and 100 °C (Display group 004, display field 3)
- Intake air temperature less than 100 °C
- Voltage supply to engine control module greater than 11 Volt.
- 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- to select "display group number 060" and confirm entry with -Q- button.
Indicated on display
System in Basic Setting 60 ->
1 2 3 4
- Check specification for throttle valve control module in display field 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 (ECM).
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 (ECM).
If the ECM 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.
- Check specification for throttle valve control module (display fields 4).
Display Group 060:
NOTE:
If the adaptation process is interrupted by the control unit, the cause could be one of the following:
- The throttle valve is unable to close completely (e.g. because of dirt).
- The harness connectors (e.g.: at throttle valve control module) are loose, not properly connected or the contacts at the connector are corroded or bent.
- Battery voltage too low.
- Throttle valve control module or wiring is faulty.
- The engine was started or the accelerator pedal was depressed during the adaptation process.
- Distortion of throttle valve housing (check bolts: 10 Nm)
When the adaptation process is interrupted the message "Function is unknown or cannot be carried out at the moment" will appear on the fault reader display. The adaptation process will start again automatically the next time the ignition is switched on (for several seconds).
- End engine basic setting by pressing the button.
- Press buttons -0- and -6- to select "End Output" function and confirm input with -Q- button.