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.

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 →
  • 68 - INTERIOR EQUIPMENT
  • 68 - INTERIOR EQUIPMENT for BODY INTERIOR - CABRIOLET
  .

• 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. → 24 - MULTIPORT FUEL INJECTION (MFI) . 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 Ω.

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. → 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 → Engine Control Module (ECM) J623 , replacing .

Assembly is performed in the reverse order of removal, noting the following:

• Install the left knee bolster →
  • 68 - INTERIOR EQUIPMENT
  • 68 - INTERIOR EQUIPMENT for BODY INTERIOR - CABRIOLET
  .

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.