The Mass Air Flow (MAF) sensor uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool. This hot wire is maintained at 200°C (392°F) above the ambient temperature as measured by a constant cold wire. The current required to maintain the temperature of the hot wire is proportional to the mass air flow. The MAF sensor then outputs an analog voltage signal to the PCM proportional to the intake air mass. The PCM calculates the required fuel injector pulse width in order to provide the desired air/fuel ratio. This input is also used in determining transmission Electronic Pressure Control (EPC), shift and torque converter clutch scheduling.
The MAF sensor is located between the air cleaner and the throttle body or inside the air cleaner assembly. Most MAF sensors have integrated bypass technology with an integrated Intake Air Temperature (IAT) sensor. The hot wire electronic sensing element must be replaced as an assembly. Replacing only the element may change the air flow calibration.
Removal & Installation
- Disconnect the negative battery cable.
- Disconnect the Mass Air Flow (MAF) sensor electrical connector
- Remove the 2 bolts, the MAF sensor and discard the gasket.
To install, reverse the removal procedure and tighten mounting bolts to 8 ft. lbs. (11 Nm).
NOTEThe MAF sensor module and body are calibrated and installed as a unit.
WARNINGDo not tamper with the MAF sensing elements located in the airflow bypass. Tampering may result in failure.
- To check voltage power to the Mass Air Flow (MAF) sensor, first turn the ignition to the OFF position.
- Disconnect the MAF sensor connector.
- Turn the ignition switch to the ON position with the engine off.
- Measure the voltage with a digital multi-meter between (VPWR) and negative battery terminal.
- The voltage reading should be greater than 10v. If not, check for an open wire, a blown fuse or faulty circuit breaker.
- To check ground circuit measure the voltage between (PWRGND) and positive battery terminal.
The voltage reading should be greater than 10v. If not, suspect an open circuit.