Manifold Pressure/Vacuum Sensor: Testing and Inspection

Diagnostic Procedures

Manifold Absolute Pressure Sensor, Checking

• Use only gold-plated terminals when servicing terminals in harness connector of Manifold Absolute Pressure (MAP) Sensor (G71 ).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test conditions

• The Engine Control Module (ECM) (J220) OK.

• The parking brake must be applied, otherwise daytime running lights are switched on.

• On vehicles with automatic transmission, selector lever must be in position "P" or "N".

• The Ground connections between engine and body must be OK.

Function test

- Connect the scan tool.

- Start engine and let it run at idle.

- Using the scan tool, Check the specified value of the Manifold Absolute Pressure (MAP) Sensor (G71) at idle:





If the specified value was obtained:

- Condition is not present at this time. Check connections for loose or damaged terminals and check harness for an intermittent short.

- Erase the DTC. Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

If the specified value was Not obtained:

Test sequence

- Disconnect the Manifold Absolute Pressure (MAP) Sensor (G71) electrical harness connector.

- Start the engine and run at idle speed.

- Using a multimeter, check the Manifold Absolute Pressure (MAP) Sensor (G71) electrical harness connector terminals 1 to 3 for voltage.

Specification: Near 5 V

- Switch the ignition OFF.

If the specified value was 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) (J220). Refer to the Repair Information.

- Using a multimeter, check the Manifold Absolute Pressure (MAP) Sensor (G71) electrical harness connector terminal to the Motronic Engine Control Module (ECM) (J220) electrical harness connector T121 for resistance.





Specified Value: 1.5 ohm max.

If the specified value was Not obtained:

- Check the wiring for an open circuit, high resistance, short circuit to each other, Battery (+) or Ground.

- 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 the voltage supply was OK:

- Replace Manifold Absolute Pressure (MAP) Sensor ( G71).

If the specified voltage supply was Not obtained:

If the manufacturers test box is being used. Perform the following step.

- Install the test box. Refer to the Repair Information.

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

- Remove the Engine Control Module (ECM) (J220). Refer to the Repair Information.

- Using a multimeter, check the Manifold Absolute Pressure (MAP) Sensor (G71) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J220) electrical harness connector T121 terminals for resistance.





Specified value: 1.5 ohms max.

If the specified value was Not obtained:

- Check the wiring for an open circuit, high resistance, short circuit to each other, Battery (+) or Ground.

- 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 Not OK:

- Replace the Motronic Engine Control Module (ECM) (J220). Refer to the 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 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 ] Monitors, Trips, Drive Cycles and Readiness Codes.