Mass Air Flow Sensor -G70-, CHECKING

The following procedure is used to diagnose the Mass Air Flow Sensor -G70- which is controlled by Engine Control Module -J623-.

Special tools and workshop equipment required 

• Multimeter
• Wiring diagram

Test Requirements 

• The Fuse -S14- fuse OK.
• 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 (GND) 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 .

Start diagnosis

-- Connect the scan tool.

-- Start engine and let it run at idle.

-- Using the scan tool, Check the air flow quantity of the Mass Air Flow Sensor -G70- at idle:

Diagnostic text	Specified value
Air flow quantity at Mass Air Flow (MAF) sensor
Engine running at idle	2.00 to 5.00 g/s

-- End diagnosis and switch ignition off.

If the specified value was obtained, but the DTC memory has a DTC indicating a Mass Air Flow Sensor -G70- fault:

-- Check the voltage supply of the Mass Air Flow Sensor -G70-, refer to "Checking Voltage Supply"  below.

If specified value was not obtained:

-- Check the wiring of the Mass Air Flow Sensor -G70-, refer to "Checking Wiring"  below.

Checking Voltage Supply 

-- Remove the engine compartment trim.

-- Remove the engine cover.

-- Disconnect the Mass Air Flow Sensor -G70- electrical harness connector.

-- Crank the engine.

-- Using a multimeter, check the Mass Air Flow Sensor -G70- electrical harness connector terminal 3 to engine Ground (GND) for voltage.

Specified value: battery voltage.

-- Switch the ignition off.

If specified value was not obtained:

-- Check the Mass Air Flow Sensor -G70- electrical harness connector terminal 2 to theStarter Relay 2 -J695- socket A6e for an open circuit or a short circuit to Ground (GND).

-- 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:

Checking Wiring 

-- Remove the Engine Control Module -J623-. Refer to the Repair Manual.

-- Using a multimeter, check the Mass Air Flow Sensor -G70- electrical harness connector terminals to the Engine Control Module -J623- electrical harness connector T94 terminals for an open circuit, high resistance or short to ground.

Mass Air Flow Sensor -G70- electrical harness connector terminals	Engine Control Module -J623- electrical connector T105 terminals
1	104
2	82
3	S 14

Specified value: 1.5 Ω max.

If any of the specified values were not obtained:

-- Check the wiring for an open circuit, a short circuit to each other, Battery voltage, or Ground (GND).

-- 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 OK:

-- Replace theMass Air Flow Sensor -G70-.

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to READINESS CODE .

-- End diagnosis.

If the DTC returns and no malfunction is found in the wiring and voltage supply was OK:

-- Replace the Engine Control Module -J623-.Refer to appropriate service information.

Assembly is performed in the reverse order of the removal, note the following:

Final Procedures 

After 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 .