With Generic Scan Tool

Charge Air Pressure Sensor G31, checking

Note:
- Use only gold-plated terminals when servicing terminals in harness connector of Charge Air Pressure Sensor G31.

Special tools, testers and auxiliary items required
- Multimeter
- Wiring diagram

Test requirements
- 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.
- On vehicles with automatic transmission, selector lever in position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.

Test procedure
- Perform a preliminary check to verify the customers complaint. Service and Repair

Start diagnosis
- Remove the engine cover with air filter.

Test sequence






- Disconnect the Charge Air Pressure Sensor G31 electrical harness connector -2-.

- Start engine and let it run at idle.






- Using a multimeter, check the Charge Air Pressure Sensor G31 electrical harness connector terminals 1 to 3 for voltage.

Specified value: min. 4.5 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 Test Box 105 Pin VAG1598/31.

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

- Remove the Motronic Engine Control Module (ECM) J220. Service and Repair






- Using a multimeter, check the Charge Air Pressure Sensor G31 electrical harness connector terminals to the Motronic Engine Control Module (ECM) J220 electrical harness connector T121 terminals for an open circuit according to wiring diagram.






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).

- If necessary, repair the faulty wiring connection.

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

If no malfunction is detected in the wiring and if the voltage supply was OK:

- Replace the Charge Air Pressure Sensor G31.

- Erase the DTC memory. Diagnostic Mode 4: Reset/Erase Diagnostic Data

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate 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 MFI Engine Control Module (ECM) J220. Service and Repair

- Assembly is performed in the reverse of the removal.

Final procedures

After the 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