See Figure 1
The Mass Air Flow (MAF) Sensor measures the amount of air entering the engine during a given time. The VCM uses the mass airflow information for fuel delivery calculations. A large quantity of air entering the engine indicates an acceleration or high load situation, while a small quantity of air indicates deceleration or idle.
See Figure 2
- Backprobe with a high impedance voltmeter between MAF sensor terminals C and B .
- With the ignition ON engine off, verify that battery voltage is present.
- If the voltage is not as specified, either the wiring to the MAF sensor, the fuse, or the VCM may be faulty. Correct any wiring or VCM faults before continuing test.
- Disconnect the voltmeter and backprobe with a frequency meter between MAF sensor terminals A and B .
- Start the engine and wait until it reaches normal idle speed and verify that the MAF sensor output is approximately 99 Hz.
- Slowly raise engine speed up to maximum recommended rpm and verify that the MAF sensor output rises smoothly to approximately 8000 Hz.
- If MAF sensor output is not as specified the sensor may be faulty.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Unplug the electrical connector.
- Remove the air intake hoses from the sensor, then remove the sensor.
- Installation is the reverse of removal.