Throttle Valve Control Module, Checking

Throttle Valve Control Module, Checking

• Use only gold-plated terminals when servicing terminals in harness connector of Mass Air Flow (MAF) Sensor (J338).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Motronic Engine Control Module (ECM) ( J623 ) 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 (Throttle Drive (for Electronic Power Control (EPC)) (G186)) in the Throttle Valve Control Module ( J338) and is operated by the Motronic Engine Control Module (ECM) (J623) according to the specifications of Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185 ).

The Throttle Valve Control Module (J338) Contains the following components:

• Throttle Drive (for Electronic Power Control (EPC)) (G186)

• Throttle Drive Angle Sensor 1 (for Electronic Power Control (EPC)) (G187)

• Throttle Drive Angle Sensor 2 (for Electronic Power Control (EPC)) (G188)

Function test

- 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) 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):





- End diagnosis and switch ignition off.

If the specified values are not obtained:

- Disconnect the Throttle Valve Control Module ( J338) electrical harness connector - 1 -.





Checking internal resistance

- Using a multimeter, check the Throttle Drive (for Electronic Power Control (EPC)) (G186) 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 specified value was not obtained:

- Replace the Throttle Valve Control Module ( J338 ) Fuel Injection and Ignition Repair Information.

If the specified value was obtained:

- Using a Multimeter, check 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 specified value was obtained:

- Replace the Throttle Valve Control Module ( J338 ) Fuel Injection and Ignition Repair Information.

If the specified value was not obtained:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box. 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) ( J623). Refer to => [ Engine Control Module 1, Removing and Installing ] Engine Control Module 1, Removing and Installing.

- Using a Multimeter, check the Throttle Valve Control Module (J338) electrical harness connector terminals to the Motronic Engine Control Module (ECM) ( J623) electrical harness connector T60 terminals for an open circuit.









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) or an open circuit.

- Check the electrical harness connector for damage, corrosion, lose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and if the voltage supply was not OK:

- Replace Motronic Engine Control Module (ECM) ( J623). Refer to => [ Engine Control Module 1, Removing and Installing ] Engine Control Module 1, Removing and Installing

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 ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End of diagnosis.