Charge Air Pressure Sensor, Checking

Observe all safety precautions: SAFETY PRECAUTIONS 

View clean working conditions: CLEAN WORKING CONDITIONS 

Prior to repair work, perform a preliminary check to verify the condition. Refer to PRELIMINARY CHECK .

Special Tools And Workshop Equipment 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 connections between engine/transmission/chassis OK.
• Ignition switched off.

Test Procedure 

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

Start Diagnosis 

-- Remove the engine cover.

Test Sequence 

-- Disconnect the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector.

-- Turn ON the ignition switch.

-- Using a multimeter, check the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals 1 to 3 for voltage.

Specified Value: Near 5 V 

-- Using a multimeter, check the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals 1 to 4 for voltage.

Specified Value: Min. 4.40 V 

-- Switch the ignition off.

If Either Specified Value Was Not Obtained: 

Checking Wiring 

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

-- Using a multimeter, check the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open circuit according to wiring diagram. Refer to Appropriate Wiring Diagrams for Pin locations.

Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals
1	66
2	30
3	17
4	83

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.

-- 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 The Voltage Supply Was Ok: 

-- Replace the Charge Air Pressure Sensor/IAT sensor -G31/G42- Refer to the Repair information.

If No Malfunction Is Detected In The Wiring And The Voltage Supply Was Not Ok: 

-- Replace the Motronic Engine Control Module (ECM) -J623-.

-- Install the engine cover.

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 .