Throttle Valve Control Module -J338-, Adaptation
Throttle Valve Control Module -J338- Adapting
The adaptation teaches the Engine Control Module (ECM) various positions of the throttle valve when the ignition is on and the engine is stopped. These positions are stored in the control module The return communication regarding the position of the throttle valve occurs via the two angle sensors for throttle drive.
An adaptation must always be performed when the throttle valve control module -J338- or the Engine Control Module (ECM) are removed and installed (or replaced) or if voltage supply to the Engine Control Module (ECM) is interrupted.
The learning process (adaptation) occurs:
- automatically if the ignition is switched on for at least 10 seconds without operating starter and accelerator pedal and the Engine Control Module (ECM) recognizes "adaptation required". (There will be no notification of whether adaptation was successful or not however). Adaptation required is recognized if stored voltage values from the angle sensors do not match actual measured voltage values within a certain tolerance range.
- via initiation of basic setting (function 04) display group 060 with ignition on.
NOTE: Engine will not start during automatic adaptation.
Special Tools and Equipment
- VAS5051 with VAG5051/1
Requirements
- No DTCs in DTC memory, check DTC memory.
- Engine not running, ignition switched on.
- Accelerator pedal not depressed.
- Coolant temperature 10 to 95 °C.
- Intake air temperature 10 to 90 °C.
- Supply voltage for Engine Control Module (ECM) more than 12.7 volts; checking.
Procedure
- Connect VAS5051 tester and select vehicle system "01 - Engine electronics". Ignition must remain switched on for this. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAS 5051 Tester, Connecting and Selecting Functions" Testing and Inspection
Display on VAS5051:
- In selection -1-, click on the diagnostic function "04 - Basic setting".
Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "060" in button field -2- for "display group number 060" and press Q button to confirm input.
After pressing Q-button, throttle valve actuator will be switched on without current.
In this condition, the throttle valve will be drawn into an emergency 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 position are stored by the Engine Control Module (ECM).
Next, the throttle valve is opened by a certain value. If this value is reached, the throttle valve actuator is once again de-energized. Now, the mechanical spring must close the throttle valve to the previously learned emergency position within a specified time (spring test).
Then, the throttle valve is closed by the throttle valve actuator; the values supplied by the angle sensors in the throttle valve control unit are stored by the Engine Control Module (ECM).
If Engine Control Module (ECM) should deenergize throttle valve actuator during driving operation, this is expressed by an increased, surging idle speed (RPM). The engine accepts gas only after great delay.
Display on VAS5051:
- Check specified values for throttle valve control module in display fields -3- and -4-.
Display Group 060:
NOTE:
The control module can abort adaptation for the following reasons:
- Throttle valve cannot be closed completely (e.g. contamination).
- Battery voltage is too low.
- Throttle valve control module or wire connection is faulty.
- Engine is started during adaptation or accelerator pedal is operated.
- Tension of throttle valve housing (check bolts).
After termination, tester displays "Function is unknown or cannot be performed at the moment". The next time the ignition is switched on (several seconds), adaptation will be automatically repeated.
- End function "04 - Basic setting" by pressing <- button.