Charge Air Pressure Sensor, Checking

Charge Air Pressure Sensor, 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 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.
- 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. General Diagnosis

Start diagnosis







- Remove engine cover - arrows -.

Test sequence







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

If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) J623.







- Using a multimeter , check the Charge Air Pressure Sensor G31 electrical harness connector terminals to the Engine Control Module (ECM) J623 electrical harness connector T94 terminals for resistance.

Charge Air Pressure Sensor Engine Control Module (ECM)
G31 electrical harness J623 electrical harness connector
connector terminals T94 terminals or test box sockets
1 53
3 19
4 38

Specified value: 1.5 Ohms max.

If the specification was not obtained:
- Check the wiring for a open circuit, short circuit to each other, Battery (+), or Ground (GND).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.

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 04 - Erase DTC Memory
- Perform a road test to verify repair.

If the DTC does not return:
Repair complete, Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was not OK:
- Replace the Engine Control Module (ECM) J623.
- 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. Diagnostic Mode 03 - Read 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. Monitors, Trips, Drive Cycles and Readiness Codes

End of diagnosis