Charge Air Pressure Sensor/Intake Manifold Temperature Sensor, Checking

Charge Air Pressure Sensor/Intake Manifold 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

• On the right side, where the compressor is with the charge air cooler. The Charge Air Pressure Sensor 2 / Intake Manifold Temperature Sensor 2 (G447 / G430) and the Charge Air Pressure Sensor / Intake Manifold Temperature Sensor (G31 / G72) are arranged as mirror images of each other.

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






- Start engine and let it run at idle.

- Using a Multimeter, check the Charge Air Pressure Sensor / Intake Manifold Temperature Sensor (G31 / G72) electrical harness connector terminals 2 to 4 for voltage.






Specified value: near 5.0 V

- Switch the ignition off.

- Continue test according to the following table:






Checking wiring

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

- Using a Multimeter, Check the Charge Air Pressure Sensor / Intake Manifold Temperature Sensor (G31 / G72) electrical harness connector to the Motronic Engine Control Module (ECM) electrical harness connector T94 for an open circuit.











Specified value: 1.5 ohms Max.

If the specified values were Not obtained:

- Check the wiring connection for an open circuit, short circuit to Battery voltage or Ground

- Check the wiring connection for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

- Go to Final procedures

If the specified values were obtained:

- If no faults were found Replace the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

- Go to Final procedures

Component Check

- Using a Multimeter , check the Charge Air Pressure Sensor / Intake Manifold Temperature Sensor (G31 / G72) terminals 3 to 4 for resistance.

Use the chart below for the specified values:

Specified values:






If any of the specified value's were Not obtained:

- Replace the Charge Air Pressure Sensor / Intake Manifold Temperature Sensor (G31 / G72). Refer to appropriate service manual.

- Go to Final procedures

If the specified values were obtained:

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

Final procedures

- Reinstall the engine cover with air filter, if necessary. Refer to the appropriate service manual.

- 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 Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

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