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 Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248) 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.

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

Test procedure

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

Start diagnosis

- Remove the engine cover.

Checking internal resistance

- Disconnect the Throttle Position Sensor G79 and Accelerator Pedal Position Sensor 2 G185 electrical harness connector.

- Using a multimeter, check the Throttle Position Sensor G79 and Accelerator Pedal Position Sensor 2 G185 terminals 1 to 3 for resistance.





Specified value: 1000 to 1500 ohms

- Depress the accelerator pedal.

Specified value: 1000 to 2500 ohms

If either specification was not obtained:

- Replace the Throttle Position Sensor G79 and Accelerator Pedal Position Sensor 2 G185.

If the specifications were obtained:

Checking wiring

- Install the test box. Refer to => [ 68-Pin Test Box Adapter, VAG1598/19, Installing ] Diesel Direct Fuel Injection ECM, Checking.

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

- Remove the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248). Refer to => [ Diesel Direct Fuel Injection ECM, Replacing ] Diesel Direct Fuel Injection ECM, Checking.

- Using a Multimeter, check the Throttle Position Sensor G79 and Accelerator Pedal Position Sensor 2 G185 electrical harness connector terminals to the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248) electrical connector for an open circuit.









Specified value: 1 ohms max.

If the specification is not obtained:

- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

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

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and if the voltage supply was OK:

- Replace the Throttle Position Sensor G79 and Accelerator Pedal Position Sensor 2 G185..

- 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 not OK:

- Replace the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) (J248). Refer to => [ Diesel Direct Fuel Injection ECM, Replacing ] Diesel Direct Fuel Injection ECM, Checking.

- Assembly is performed in the reverse of the removal.

Final procedures

After the 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.