P0101

CIRCUIT DESCRIPTION

Schematic:

The Mass Air Flow (MAF) sensor is an air flow meter that measures the flow rate and densily of the air entering the engine. The MAF sensor receives power and ground from circuits not supplied by the control module. The control module does apply a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on inlet air flow through the sensor. A low air flow rate (such as engine idle) causes the MAF sensor to produce a low frequency signal. A high air flow rate (such as wide open throttle, or high load) causes the MAF sensor to produce a high frequency signal.

The PCM uses the MAF sensor signal to provide the correct fuel delivery for a wide range of engine speeds and loads. The PCM tests the sensor to verify the actual MAF signal. The PCM uses the MAP sensor, TP sensor, and the engine speed to calculate a predicted MAF value. Then, the PCM compares the actual MAF to the predicted MAF. If the difference between the actual MAF and the predicted MAF is more than a calibrated amount, DTC P0101 will set.

CONDITIONS FOR RUNNING THE DTC
^ No TP sensor, MAP sensor, or system voltage DTCs are set.
^ Ignition voltage is between 11 volts and 18 volts.
^ Canister purge duty cycle is less than or equal to 90 percent.
^ Total EGR pintle valve movement is less than 90 percent.
^ Throttle angle is steady and less 48 percent.
^ MAP is steady and less than 59 kPa.

CONDITIONS FOR SETTING THE DTC
^ The difference between the actual MAF and the predicted MAF is more than the calibrated amount.
^ The condition is present for at least 2.5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

For intermittent conditions, refer to Symptoms. Symptom Related Diagnostic Procedures

TEST DESCRIPTION

Steps 1 - 9:

The numbers below refer to the step numbers on the diagnostic table.
2. Since calculated MAF is based on many inputs, these DTCs should be diagnosed first.