Throttle Valve Control Module, Checking
Throttle Valve Control Module, Checking
• Use only gold-plated terminals when servicing terminals in harness connector of Throttle Valve Control Module (J338).
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Motronic Engine Control Module (ECM) (J220) fuses OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position " P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Throttle valve must not be damaged or dirty.
• Coolant Temperature at least 80° C.
Function
Throttle valve operation occurs by an electric motor (Accelerator Pedal Position Sensor 2 (G185)) in Throttle Valve Control Module ( J338). It is operated by Motronic Engine Control Module (ECM) (J220) according to specifications of Throttle Position (TP) Sensor (G79)/ Accelerator Pedal Position Sensor 2 (G185).
Components of Throttle Valve Control Module (J338 ):
• Throttle Position (TP) Sensor (G79)
• Accelerator Pedal Position Sensor 2 (G185)
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check
Start diagnosis
- Connect the scan tool.
- Switch ignition on.
- Using the scan tool, check the throttle valve position (absolute) at idle stop:
- Slowly depress the accelerator pedal to Wide Open Throttle (WOT) stop while observing the percentage display. The percentage display must increase uniformly.
- Using the scan tool, check the throttle valve position (absolute) at Wide Open Throttle (WOT) stop:
- End diagnosis and switch ignition off.
If the specified values are not obtained:
- Remove the air hose - arrows -.
- Disconnect the Throttle Valve Control Module ( J338) electrical harness connector - 3 -.
Checking internal resistance
- Using a multimeter, check the Accelerator Pedal Position Sensor 2 (G185) at the Throttle Valve Control Module (J338) terminals 3 to 5 for resistance.
Specified value: 1.0 to 5.0 ohms (at 20° C)
If the specification was not obtained:
- Replace the Throttle Valve Control Module ( J338 ). Refer to Fuel Injection and Ignition Repair Information
If the specification was obtained:
- Check the voltage supply of the Throttle Valve Control Module (J338) to the Motronic Engine Control Module (ECM) (J220).
Checking voltage supply and wiring
- Switch the ignition on.
- Using a Multimeter, check the Accelerator Pedal Position Sensor 2 (G185) at the Throttle Valve Control Module (J338) electrical harness connector terminals 2 to 6 for voltage.
Specified value: at least 4.5 V
- Switch the ignition off.
If the specification was obtained:
- Replace the Throttle Valve Control Module ( J338 ). Refer to Fuel Injection and Ignition Repair Information
If the specification was not obtained:
Checking wiring
If the manufacturers test box is being used, perform the following step.
- Install the test box (VAG1598/31). Refer to Fuel Injection and Ignition Repair Information
If the manufacturers test box is not being used, perform the following step.
- Remove the Motronic Engine Control Module (ECM) ( J220). Refer to => [ Engine Control Module, Replacing ] Engine Control Module, Replacing.
- Using a Multimeter, check the Accelerator Pedal Position Sensor 2 (G185) at Throttle Valve Control Module (J338) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J220) electrical harness connector terminals for resistance.
Specified value: 1.5 ohms max.
If the specification is not obtained:
- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
- If necessary, repair the faulty wiring connection.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
If no malfunction is detected in the wiring and if the voltage supply was not OK:
- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) (J220). Refer to => [ Engine Control Module, Replacing ] Engine Control Module, Replacing.
- Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.
End of diagnosis