Throttle Position Sensor: Testing and Inspection

Throttle Position (TP) Sensor G79 / Accelerator Pedal Position Sensor 2 G185, Checking

Special tools, testers and auxiliary items required
- Multimeter V.A.G 1526 or equivalent.
- Test Box 105 Pin VAG1598/42.
- Adapter Lead Vag1598/39 VAG1598/39.
- Adapter cable V.A.G 1598/39-1.

NOTE: The Throttle Position (TP) Sensor G79 / Accelerator Pedal Position Sensor 2 G185 is located in the accelerator pedal module and communicate the drivers intensions to the SIMOS Control Module J361 completely independently of each other. Both sensors are located in the accelerator pedal module and replaced as an entire assembly.

Test requirements
- The fuses for the engine electronics OK.
- The battery voltage must be at least 12.5 Volts.
- All the electrical consumers such as, for example, lights and rear window defroster must be switched off.
- The parking brake must be applied, otherwise the daytime running lights are switched on.
- On vehicles with an automatic transmission, the selector lever must be in position "P" or "N".
- If the vehicle is equipped with an A/C system, it must be switched off.
- The ground (GND) connections between the engine and body must be OK.

Procedure
- Remove the left knee bolster







- Disconnect the electrical harness connector - 2 -.

Checking voltage supply

- Switch the ignition on.







- Using the Multimeter V.A.G. 1526 A or equivalent, check the following wiring connections for voltage.

Harness connector Terminal Specified value
1 to Ground (GND) about 5 V
1 to 5 about 5 V
2 to Ground (GND) about 5 V
2 to 3 about 5 V

- Switch the ignition off.

If the specified values are not obtained:

Checking wiring connections

- Connect the Test Box 105 Pin VAG1598/42 to the wiring harness of the Engine Control Module (ECM) J623. The ECM is not connected.







- Using the Multimeter V.A.G. 1526 A or equivalent, check the following wiring connections for open circuit.

Harness connector Terminal Test box Socket
1 58
2 80
3 78
4 79
5 56
6 57

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.

If no malfunction is detected in the wiring and if the voltage supply was not OK:
- Replace the Engine Control Module (ECM) J623.

Assembly is performed in the reverse order of removal, noting the following:
- Install the left knee bolster.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.

- End diagnosis and switch the ignition off.