Accelerator Pedal 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.
- Wiring diagram.

Test requirement
- The 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.

NOTE:
- Use only gold-plated terminals when servicing the electrical harness connector terminals in Throttle Position (TP) Sensor G79 / Accelerator Pedal Position Sensor 2 G185.
- 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 Engine Control Module (ECM) J623 completely independently of each other. Both sensors are located in the accelerator pedal module and replaced as an entire assembly.

Test sequence
- Remove the left knee panel.







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

Checking voltage supply
- Switch the ignition on.







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

Throttle Position (TP) Sensor G79 / Specified
Accelerator Pedal Position Sensor 2 G185 value
electrical harness connector terminals
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 specification was 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 Engine Control Module (ECM) J623.







- 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 T94 for an open circuit.

Throttle Position (TP) Sensor Engine Control Module
G79 / Accelerator Pedal (ECM) J623 electrical
Position Sensor 2 G185 connector T94 terminals
electrical harness connector or test box sockets
terminals
1 58
2 80
3 56
4 57
5 78
6 79

Specified value: 1.5 Ohms max.

If the specification was not obtained:
- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
- Check the electrical harness connector for damage, corrosion, lose 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 (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.
- Install the left knee panel.

Final procedures
After repair work, the following work steps must be performed in the following 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.