Charge Air Pressure Sensor, Checking

Charge Air Pressure Sensor, Checking

• 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. Refer to => [ Preliminary Check ] Preliminary Check

Start diagnosis

- Remove the engine cover with air filter. Refer to repair information.

Test sequence

- Disconnect the Charge Air Pressure Sensor (G31) electrical harness connector - arrow -.





- 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. Refer to repair information.

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

- Remove the Motronic Engine Control Module (ECM) (J220). Refer to repair information.

- 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 T94 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). Refer to repair information.

If no malfunction is detected in the wiring and if the voltage supply was not OK:

- Replace the Motronic Engine Control Module (ECM) (J220). Refer to repair information.

- Install the engine cover with air filter Refer to repair information.

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 ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.