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) (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.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to --> [ Preliminary Check ] Preliminary Check

Start diagnosis

Function

Throttle valve operation occurs via an electric motor (Throttle Drive (for Electronic Power Control (EPC)) (G186)) in Throttle Valve Control Module (J338). It is operated by Motronic Engine Control Module (ECM) (J623) according to specifications of Throttle Position (TP) Sensor (G79).

Components of Throttle Valve Control Module (J338):

• 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) 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 Throttle Valve Control Module (J338 ) far enough so that the electrical connector terminals are reached.

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





Checking 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 specification was not obtained:

- Replace the Throttle Valve Control Module (J338)24 Description and Operation

If the specification was obtained:

- Check the voltage supply of the Throttle Valve Control Module (J338) to the Motronic Engine Control Module (ECM) (J623).

Checking voltage supply and wiring

- Switch the ignition on.

- Using a Multimeter, check the Throttle Drive (for Electronic Power Control (EPC)) (G187) 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 not obtained:

- Using a Multimeter, check the Throttle Drive (for Electronic Power Control (EPC)) (G186) at 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).

- If necessary, repair the faulty wiring connection.

- 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 ] Monitors, Trips, Drive Cycles and Readiness Codes.

- 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) (J623).

- 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 ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End of diagnosis.