Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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.
- 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 →
- 68 - INTERIOR EQUIPMENT
- 68 - INTERIOR EQUIPMENT for BODY INTERIOR - CABRIOLET
- 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/Accelerator Pedal Position Sensor 2 G185 electrical harness connector terminals | 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 specification was not obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box. Refer to → 24 - FUEL INJECTION SYSTEM .
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 (ECM) J623 , Removing and Installing .
- 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 G79/Accelerator Pedal Position Sensor 2 G185 electrical harness connector terminals | Engine Control Module (ECM) J623 electrical connector T94 terminals or test box sockets |
|---|---|
| 1 | 58 |
| 2 | 80 |
| 3 | 56 |
| 4 | 57 |
| 5 | 78 |
| 6 | 79 |
Specified value: 1.5 Ω 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. → 20 - FUEL SUPPLY SYSTEM .
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 (ECM) J623 , Removing and Installing .
- Install the left knee panel →
- 68 - INTERIOR EQUIPMENT
- 68 - INTERIOR EQUIPMENT for BODY INTERIOR - CABRIOLET
Final procedures
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory.
- If necessary, erase the DTC memory. Refer to Diagnostic Mode 04: Reset/delete Diagnostic Data .
- If the DTC memory was erased, generate readiness code. Refer to Readiness Code .
- End diagnosis and switch the ignition off.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.