The Mass Air Flow (MAF) sensor detects the intake air quantity and converts the measurement to a voltage reading by way of a heated resistor. The voltage signal is sent to the Powertrain Control Module (PCM) which, in turn, determines such things as fuel injection quantities and engine speed.
See Figures 1, 2 and 3
- Make sure the ignition is OFF .
- Connect jumper wires from the sensor terminal to the wiring harness connector. This permits the engine to operate normally while you check the sensor.
- Connect a Digital Volt Ohmmeter (DVOM) between the jumper wires.
- Check for voltage at the MAF sensor connections. On OBD-I systems, test terminals MAF and SIG RTN. On OBD-II systems, check MAF and GND. Refer to the wiring illustrations.
- Turn the ignition switch to the ON position, but do not start the engine. The voltage should be 1.0-1.5 volts.
- Start the engine, then check the voltage, which should be 1.5-5.0 volts.
- If the voltage readings do not meet specifications, replace the sensor.
- Remove the jumper wires.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Unplug the Mass Air Flow (MAF) sensor electrical connector.
- Unplug the Intake Air Temperature (IAT) sensor electrical connection.
- Loosen the clamp attaching the air cleaner-to-intake manifold tube to the MAF sensor, and remove the tube from the sensor.
- Disconnect the vacuum hose and remove the upper engine air cleaner.
- Loosen the MAF sensor bolts and remove the sensor.
- Install the MAF sensor and tighten the retaining bolts to 71-88 inch lbs. (8-10 Nm).
- Install the upper engine air cleaner and connect the vacuum hose.
- Connect the air cleaner-to-intake manifold tube to the MAF sensor and tighten the clamp.
- Connect the IAT sensor electrical connection.
- Connect the MAF sensor electrical connection.
- Connect the negative battery cable.