1215 - Air Mass Meter

Air flow sensor, checking:

On cars with DME 3.3.1 a Hot Film Mass Air Flow Sensor is used. When the engine is running, a current is used to heat a thin film in the center of the meter. The current used to heat the film is electronically converted into a voltage measurement corresponding to the mass of intake air.

If the hot film breaks or if there is no output from the air flow sensor, the ECM automatically switches to a "fail-safe" mode and turns on the Check Engine light. The engine can usually be started and driven.

- Disconnect the harness connector at the air flow sensor.

- Turn the ignition on and check for voltage and ground at the connector.

Pin 1 = ground
Pin 3 = positive (+) battery voltage

If any faults are found, check for wiring breaks between the air flow sensor and the ECM and between the air flow sensor and the main relay. Also check the operation of the main relay.

Refer to Diagrams / Electrical for schematics.

NOTE: The air flow sensor has no internal moving parts and cannot be serviced or adjusted.