Charge Air Pressure Sensor/Intake Air Temperature Sensor, Checking

Charge Air Pressure Sensor/Intake Air Temperature Sensor, Checking

Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.

For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.

Special tools, testers and auxiliary items required

• Multimeter

• Wiring diagram

Test requirements

• 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.

• 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 appropriate service manual.





Test sequence

- Disconnect the Charge Air Pressure Sensor/Intake Air Temperature Sensor (G31/G72) electrical harness connector - 1 -.

On the right side, on the compressor with the charge air cooler. Note: The intake air temperature sensor 2 -G430- / charge air pressure sensor 2 -G447- are arranged as mirror images of each other.





- Start engine and let it run at idle.

- Using a multimeter, check the Charge Air Pressure Sensor/Intake Air Temperature Sensor (G31/G72) electrical harness connector terminals 1 to 2 for voltage.





Specified value: min. 4.5 V

- Switch the ignition off.

If the specification was obtained:

- Replace the Charge Air Pressure Sensor/Intake Air Temperature Sensor (G31/G72).

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 Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

- Using a multimeter, check the Charge Air Pressure Sensor/Intake Air Temperature Sensor (G31/G72) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623)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, loose or broken terminals.

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

- Replace the Charge Air Pressure Sensor/Intake Air Temperature Sensor (G31/G72).

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 appropriate service manual.

- Install the engine cover with air filter. Refer to appropriate service manual.

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.