Downshift Switch: Testing and Inspection
Throttle Position (TP) Sensor G79 / OR Kick Down Switch/Closed Throttle Position Switch F8/F60 , Checking
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram
Test requirement
- The Motronic Engine Control Module (ECM) J220 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.
Test sequence
- Remove the drivers side storage compartment.
- Disconnect the Throttle Position (TP) Sensor G79 / Accelerator Pedal Position Sensor 2 G185 6-pin electrical harness connector.
Checking voltage supply and wiring
- Switch the ignition on.
- Using a Multimeter, check the following wiring connections for voltage.
Throttle Position (TP) Sensor Specified Value
G79 / OR Kick Down Switch/
Closed Throttle Position Switch
F8/F60, checking
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 is not obtained:
If the manufacturers test box is being used. Perform the following step.
- Install the test box.
- Using a Multimeter, check the Throttle Position (TP) Sensor G79 / Accelerator Pedal Position Sensor 2 G185 6-pin electrical harness connector terminals to the Motronic Engine Control Module (ECM) J220 electrical connector T94 for an open circuit according to wiring diagram.
Throttle Position (TP) Sensor Motronic Engine Control Module
G79 / OR Kick Down Switch/ (ECM) J220 electrical connector
Closed Throttle Position Switch T94 terminals or test box socket
F8/F60, checking
1 58
2 80
3 78
4 79
5 56
6 57
Specified value: 1.5 ohms 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, lose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Throttle Position (TP) Sensor G79 / OR Kick Down Switch/Closed Throttle Position Switch F8/F60 , checking.
If no malfunction is detected in the wiring and if the voltage supply was not OK:
- Replace the Motronic Engine Control Module (ECM) J220.
- Install the drivers side storage compartment.
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. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code.
- End of diagnosis.