Programming and Relearning
Throttle Valve Control Module -J338-, Adaptation
In the adaptation process, the engine control module learns various throttle valve positions with the ignition switched on and the engine stopped. These positions are stored in the control module. Feedback on the position of the throttle valve is provided by the two throttle valve drive angle sensors.
Adaptation must always be performed if the Throttle valve control module -J338- or the engine control module is removed and installed/replaced or if the engine control module power supply is interrupted.
Adaptation is implemented:
Automatically if ignition is switched on for at least approx. 10 seconds without actuating the starter and accelerator pedal and the engine control module recognizes that "learning is required" (it is however not possible to see whether or not adaptation has been performed successfully). "Learning required" is recognized if stored voltage values from the angle sensors do not coincide with currently measured voltage values within a certain tolerance range.
By initiating basic setting (function 04), display group 060 with ignition on.
NOTE: The engine does not start during automatic adaptation.
Conditions for adaptation of throttle valve control module
- No faults stored in fault memory, Interrogating fault memory
- Engine stopped, ignition on
- Accelerator pedal not pressed
- Coolant temperature 10 ... 95 degree C
- Intake air temperature 10 ... 90 degree C
- Supply voltage for engine control module greater than 11 V; checking
Work sequence
- Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 - Engine electronics" from list. Ignition must be on. Connecting VAS 5051 Scan Tool
Indicated on VAS 5051:
- From list -1- select diagnostic function "04 - Basic setting".
Indicated on VAS 5051:
1 Enter display group
- Use keypad -2- to enter "060" for "Display group number 060" and confirm by touching Q key.
Indicated on VAS 5051:
- Activate basic setting by touching key -A-.
- Check display in zones -3- and -4-.
Throttle valve actuator is initially de-energized.
In this condition, the throttle valve is pulled into an emergency running position by a mechanical spring in the throttle valve control module. The values supplied by the two angle sensors in this emergency running position are stored by the engine control module.
The throttle valve is then opened a certain amount. Once this value is attained, the throttle valve actuator is de-energized again. The mechanical spring then has to close the throttle valve within a certain period to the previously learned emergency running position (spring test).
The throttle valve is then closed by the throttle valve actuator; the values provided by the angle sensors in the throttle valve control module are stored in the engine control module.
De-energization of the throttle valve actuator by the engine control module while driving becomes apparent in the form of a higher uneven idling speed. There is only a very slow throttle response.
- Check specification for throttle valve control module (display zones 3 and 4, during adaptation).
Display Group 060:
- Check specification for throttle valve control module (display zones 3 and 4, after adaption).
Display Group 060:
NOTE: The abbreviation "ADP" in display zone 4 stands for "Adaptation".
NOTE: Possible causes if adaptation is terminated by the control module and "Function unknown or cannot be implemented at present" or some other fault message is indicated on the tester:
- Failure to comply with all test conditions
- Engine started during adaptation process or accelerator pedal pressed
- Throttle valve cannot be completely closed (e.g.dirty)
- Connector (6-pin) at throttle valve control module not engaged
- Wiring faulty
- Throttle valve housing strained (check bolted joint)
- Throttle valve control module faulty
- Terminate function "04 - Basic setting" by touching <- key.