Throttle Valve Control Module -J338-, Adaptation
Throttle Valve Control Module -J338-, 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 actuator angle sensors.
If the Throttle valve control module -J338- or the engine control module are removed, installed or replaced or if the voltage supply from the engine control module is interrupted, adaptation must always be performed.
The learning process (adaptation process) is performed:
- Automatically if the ignition is switched on once for at least 10 seconds without activating the starter or the accelerator pedal and the engine control module recognizes "adaptation requirement". In this case, 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.
- By initiating the basic setting (Function 04) of display group 060 with ignition switched on.
NOTE: Engine will not start during automatic adaptation.
Special tools and equipment
- VAS5051 with VAS5051/1
Requirements
- No DTCs recorded in DTC memory; check Diagnostic Trouble Code (DTC) memory.
- Engine stopped, ignition switched on
- Accelerator pedal not depressed.
- Engine coolant temperature 10 to 95 degrees C
- Intake air temperature 10 to 90 degrees C
- Voltage supply to engine control module greater than 12.7 V, Testing.
Procedure
- Connect testing and information system VAS5051 and select vehicle system "01 -Engine electronics" in selection. Ignition must be switched on.
Display on VAS5051:
- Under -1- select diagnostic function "04 - Basic setting".
Display on VAS5051:
1. Enter display group
- Enter "060" for "display group number 060" in zone -2- and confirm entry by pressing -Q- button.
Display on VAS5051:
- Activate basic setting by pressing -A- button.
- Check specifications for throttle valve control module in display zones -3- and -4-.
All models
The throttle valve actuator is first connected without current.
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 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 module are stored in the engine control module.
If the engine control module 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.
NOTE: "ADP" in display zone 4 stands for "Adaptation".
NOTE: If the adaptation is interrupted by the control module, 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 module or wiring is faulty.
- Engine was started or accelerator was activated during the adaptation process.
- Distortion of throttle valve housing (check screw connection).
When adaptation 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 adaptation process is automatically performed again.
- Exit function "04 - Basic setting" by pressing square button.