Air Flow Meter/Sensor

MASS AIR FLOW SENSOR

Description
The type of air flow sensor is a hot film and composed of a hot film sensor, housing, metering duct (power transistor, sensor element).
Mass air flow rate is measured by detection of heat transfer from a hot film probe and the change of the mass air flow rate causes change in the amount of heat being transferred from the hot wire probe surface to the air flow. This results in the change of the temperature of the hot wire probe and in the change of resistance.





Circuit Diagram





Troubleshooting Procedures

Troubleshooting Hints
1. If the engine stalls occasionally, crank the engine and shake the mass air flow sensor harness. If the engine stalls, check the poor contact of the mass air flow sensor connector.
2. If the mass air flow sensor output voltage is other than the ignition switch is turned on (do not start the engine). Check for the faulty mass air flow sensor or engine control module.
3. If the engine can be idle even if the mass air flow sensor output voltage is out of specification, check for the following conditions;
- Disturbed air flow in the mass air flow sensor Disconnected air duct, clogged air cleaner filter.
- Poor combustion in the cylinder. Faulty ignition plug, ignition coil, injector, incorrect compression
- Air leaks in the intake manifold





Using Scan Tool





Using Voltmeter

NOTE: When the vehicle is new (within initial operation of about 300 miles, the mass air flow sensor air quantity may be about 10% higher.














Harness Inspection Procedure