Throttle Position Sensor: Testing and Inspection

Throttle Position Sensor and Accelerator Pedal Position Sensor 2, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram

Test requirement

• 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 connections between engine/transmission/chassis OK.

• Ignition off

Test procedure

- Observe safety precautions. Refer to => [ Safety Precautions ] Safety Precautions

- Observe Clean Working Conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions

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

Start diagnosis

• Use only gold-plated terminals when servicing the electrical harness connector terminals in Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185).

Test sequence

- Remove the steering column cover.

- Disconnect the Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185) electrical harness connector.

Checking voltage supply and wiring

- Switch the ignition on.

- Using a multimeter, check the following wiring connections for voltage.










- Switch the ignition off.

If the specified values were not obtained:

Checking wiring

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

- Install the test box.

If the manufacturers test box is not being used. Perform the following step.

- Remove the Motronic Engine Control Module (ECM) (J623). Refer to the repair information.

- Using a multimeter, check the Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical connector T94 for resistance.










Specified value: 1.5 ohms max.

If the specified value is not obtained:

- Check the wiring for high resistance, an open or a short to voltage or ground.

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

- If necessary, repair the faulty wiring connection.

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

If the DTC does return, no malfunction is detected in the wiring and the voltage supply is OK:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to the repair information.

- Assembly is performed in the reverse of the removal.

Final procedures

After repair work, the following work steps must be performed in the mentioned sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.