Air Flow Meter/Sensor: Testing and Inspection

CIRCUIT DIAGRAM















HARNESS INSPECTION PROCEDURES

TROUBLESHOOTING HINTS
1. If the engine stalls occasionally, start the engine and shake the MAF sensor harness. If the engine stalls, check for poor contact at the MAF sensor connector.
2. If the MAF sensor output voltage is other than 0 when the ignition switch is turned on (do not start the engine). Check for the faulty MAF sensor or ECM.
3. If the engine can be idle even if the MAF sensor output voltage is out of specification, check for the following conditions;
- Disturbed air flow in the MAF sensor, disconnected air duct, and clogged air cleaner filter.
- Poor combustion in the cylinder, faulty ignition plug, ignition coil, injector, and incorrect comparison.
4. Though no MAF sensor malfunction occurs, check the mounting direction of MAF sensor.





USING VOLTMETER

NOTE:
1. When the vehicle is new [within initial operation of about 500 km (300 miles)], the mass air flow sensor air quantity will be about 10% higher.
2. Use an accurate digital voltmeter.
3. Before checking, warm up the engine until the engine coolant temperature reaches 80 to 90 °C (176 to 198 °F).