Throttle Position Sensor: Testing and Inspection

Throttle Position Sensor/Accelerator Pedal Position Sensor 2, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram

Test requirement

• The Engine Control Module (ECM) (J623) fuses OK.

• Battery voltage at least 12.5 V.

• 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.

• Note: both the Throttle Position (TP) sensor and - G79 and the Accelerator Pedal Position Sensor 2- G185 are located in one housing at the accelerator pedal.

• 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 procedure

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

Start diagnosis

- Remove the left knee bolster.





- Disconnect the electrical harness connector - 2 -.

Checking voltage supply

- Switch the ignition on.

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









- Switch the ignition off.

If the specified values are not obtained:

Checking wiring connections

If the manufacturers test box is being used, perform the following step.

- Install the test box (VAG1598/42).

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

Remove the Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Replacing ] Engine Control Module, Replacing

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









Specified value: Wire resistance max 1.5 ohms

If the specification is not obtained:

- Check the wiring for a short circuit to Battery positive (+) or an open circuit.

- 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 (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185). Note: both sensors are contained within one housing.

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

- Replace the Engine Control Module (ECM) (J623). Refer to=> [ Engine Control Module, Replacing ] Engine Control Module, Replacing

Assembly is performed in the reverse order of 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 diagnosis