Throttle Position Sensor And Accelerator Pedal Position Sensor 2, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram

Test requirement 

• The Motronic 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.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .

Start diagnosis 

-- Remove the drivers side storage compartment. Refer to STORAGE COMPARTMENTS, COVERS AND TRIM .

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

Checking voltage supply and wiring

-- 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 any of the specified values are not obtained:

Checking wiring 

If the manufacturers test box is being used. Perform the following step.

-- Install the Test Box 105 Pin VAG1598/42.

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

-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, 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 Motronic Engine Control Module (ECM) -J623- electrical connector T94 for resistance.

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

Specified value: 1.5 Ω max.

If the specification is not obtained:

-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

If no malfunction is found in wiring:

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to READINESS CODE .

-- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and 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 Motronic Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REMOVING AND INSTALLING .

Final procedures 

After the 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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .