For 1990-2009 cars

The mass airflow (MAF) sensor measures the speed and density of air entering the intake manifold. The ECM converts this input to a mass of air per unit time to correctly fuel the engine. The MAF output voltage is a function of the power required to keep the sensing element at a fixed temperature above outside air temperature as the incoming air cools the sensing elements. The output voltage varies between 0.14-4.8 volts under all normal engine running conditions. DTC P0103 sets when the MAF sensor signal voltage at the ECM is above the calibrated voltage value.

### DTC Parameters

DTC P0103 will set if the MAF sensor signal voltage is greater than 4.8 volts when:

• | Engine run time is longer than 0.3 seconds

• | Battery voltage is greater than 11.0 volts

• | No TP sensor DTCs have been set

DTC P0103 diagnostic runs continuously once the above conditions have been met.

P0103 is a type B DTC.

### Diagnostic Aids

To locate an intermittent problem, use the scan tool to monitor the MAF SENSOR with the ignition On, and the engine Off. Wiggling the wires while watching for a change in the MAF SENSOR voltage may locate the area where a short to voltage in the wiring could lie.

If the ECM loses the MAF sensor signal, it will calculate airflow based on the MAP, the engine speed and the TP sensors.

Circuit 416 (CMP/EGR/MAF/MAP sensor), circuit 2709 (AC pressure/fuel tank pressure sensor) and circuit 1164 (APP sensor 1) share the same 5-volt reference supply (5 volt Ref-A).

The CMP/ECT/IAT/EGR/MAF/MAP/TP1/TP2 sensors share the same sensor return circuit 652.

Important: A direct short to voltage on circuit 652 may cause internal damage to the ECM ground trace, or open the sensor element in the ECT, IAT, and/or MAP sensor.