Manifold Absolute Pressure Sensor/Intake Air Temperature Sensor, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Coolant Temperature at least 80 °C.
• Ignition switched Off.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Checking voltage supply 

-- Disconnect the Manifold Absolute Pressure Sensor -G71- /Intake Air Temperature Sensor -G42- electrical harness connector.

-- Turn ignition on

-- Using a multimeter, check the Manifold Absolute Pressure Sensor -G71- /Intake Air Temperature Sensor -G42- electrical harness connector terminal 3 to engine Ground.

Specified value: 5V.

-- Switch the ignition Off.

If the specified value was Not obtained: 

-- Check the Manifold Absolute Pressure Sensor -G71- /Intake Air Temperature Sensor -G42- electrical harness connector terminal 3 to the Engine Control Module (ECM) -J623- terminal T105/48 for resistance.

Specified value: 1.5 Ω max.

If the wiring is OK, replace the Engine Control Module -J623-.

If the specified value was obtained: 

Checking electrical circuit 

-- Remove the Engine Control Module (ECM) -J623-.

-- Using a multimeter, check the Manifold Absolute Pressure Sensor -G71- /Intake Air Temperature Sensor -G42- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T105 terminals for resistance.

Manifold Absolute Pressure Sensor -G71- /Intake Air Temperature Sensor -G42- electrical harness connector terminals:	Engine Control Module (ECM) -J623- electrical connector T105 terminals:
1	33
2	51
3	48
4	52

Specified value: 1.5 Ω max.

If the specified value was Not obtained: 

-- Check the wiring for an open, high resistance or short to 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 Sensor -G71- /Intake Air Temperature Sensor -G42-.

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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .