Mass Airflow Sensor -G70-, CHECKING

Function

The Engine Control Module - J623- uses the Mass Airflow Sensor -G70- signal to calculate a correction value for the charge air pressure. Evaluation of the signal gives consideration to the influence of temperature on the density of the charge air.

Special tools and workshop equipment required

Multimeter
Wiring Diagram
Scan Tool

Test requirements

Fuses OK.
Battery voltage OK
Switch OFF all electrical and electronic accessories.
Vehicles with Auto. Transmission, ensure Selector Lever position is in "P".
Vehicles with Man. Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
Coolant Temperature: ≥ 80 °C.
Observe all safety precautions. Refer to: SAFETY PRECAUTIONS .
View clean working conditions. Refer to: CLEAN WORKING CONDITIONS .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to: PRELIMINARY CHECK . -- Was complaint verified?	YES: GO TO Step 2 Mass Airflow Sensor -G70-, CHECKING . NO: GATHER more information from customer about the complaint.
2	CONNECT: Scan tool. START: Engine and let Idle. CHECK: Air flow quantity at Mass Air Flow sensor. SPECIFIED VALUE: About 2.00 to 5.00 g/s. IGNITION: OFF. -- Was Value obtained?	YES: Fault may be intermittent. Check the harness connector for damage, corrosion, loose or broken terminals. If necessary, repair the faulty wiring connection. GO TO Step 5 Mass Airflow Sensor -G70-, CHECKING . NO: GO TO Step 3 Mass Airflow Sensor -G70-, CHECKING .
3	DISCONNECT: Mass Airflow Sensor -G70- harness connector. IGNITION: ON. CHECK: Mass Airflow Sensor -G70- harness connector terminals 1 to ground for voltage. SPECIFIED VALUE: Battery voltage. IGNITION: OFF. -- Was Value obtained?	YES: GO TO Step 4 Mass Airflow Sensor -G70-, CHECKING . NO: CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. REPLACE: Any open fuses. GO TO Step 5 Mass Airflow Sensor -G70-, CHECKING .
4	REMOVE: Engine Control Module - J623-. Refer to appropriate repair service information. CHECK: Mass Airflow Sensor -G70- harness connector terminal 2 to the Engine Control Module - J623- harness connector T94 / 64 for resistance. CHECK: Mass Airflow Sensor -G70- harness connector terminal 3 to the Engine Control Module - J623- harness connector T94 / 13 for resistance. CHECK: Mass Airflow Sensor -G70- harness connector terminal 4 to the Engine Control Module - J623- harness connector T94 / 42 for resistance. CHECK: Mass Airflow Sensor -G70- harness connector terminal 5 to the Engine Control Module - J623- harness connector T94 / 22 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	YES: REPLACE: Mass Airflow Sensor -G70-. Refer to appropriate repair service information. GO TO Step 5 Mass Airflow Sensor -G70-, CHECKING . NO: CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO Step 5 Mass Airflow Sensor -G70-, CHECKING .
5	Final Procedure Perform a road test to verify repair. Do any DTC's return:	YES: FAULT DOES RETURN: REPLACE: Engine Control Module - J623-. Refer to appropriate repair service information. FAULT DOES NOT RETURN: Check the DTC memory. Refer to: DIAGNOSTIC MODE 03 - READ DTC MEMORY . Perform the diagnostic procedure for that DTC. NO: Repair is complete. Generate readiness code. Refer to: READINESS CODE . Return vehicle to Customer.