The Mass Air Flow (MAF) sensor measures the amount of air entering the engine during a given time. The ECM 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 1
- 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, fuse or the ECM may be faulty. Correct any wiring or ECM faults before continuing the 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 2000 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
See Figures 2 and 3
- Disconnect the negative battery cable.
- Detach the electrical connector from the MAF sensor.
- For the 3.1L engine, remove the MAF sensor from the air cleaner housing.
- For the 3.4L engine, remove the air cleaner and duct assembly. Loosen the sensor retaining clamp and remove the sensor.
- For the 3.8L engine, remove the fresh air duct from the throttle body and air cleaner assembly. Remove the retaining screws, then remove the MAF sensor from the throttle body.
- For the 3.8L engine, position the MAF sensor to the throttle body and secure with the 3 retaining screws.
- For the 3.4L engine, position the sensor and fasten the retaining clamp. Install the air cleaner and duct assembly.
- For the 3.1L engine, carefully install the MAF sensor to the air inlet grommet. Install the MAF sensor to the air inlet duct.
- Attach the electrical connector, then connect the negative battery cable.