Standard Models (Non-Alternative Fuels)

CIRCUIT DESCRIPTION
The Mass Air Flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The Powertrain Control Module (PCM) uses the MAF sensor frequency signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The PCM uses the Barometric Pressure (BARO) at key ON, and the engine RPM in order to calculate a predicted MAF value. The PCM compares the actual MAF sensor frequency signal to the predicted MAF value in order to determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 will set if the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0121, P0122, P0123, P0335, P0336, P0401, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1121, P1122, P1441 are not set.
^ The engine is running.
^ The ignition 1 signal is between 11-18 volts.
^ The Throttle Position (TP) sensor angle is steady within a range of 5 percent or less.
^ The TP sensor angle is less than 95 percent.
^ The MAP sensor is less than 80 kPa.
^ All of the above conditions are present for at least 2 seconds.

CONDITIONS FOR SETTING THE DTC
^ The actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value.
^ The above condition is present for 8 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic has been run and failed.
^ The PCM will store the conditions which were present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ Use the scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS
Inspect for the following conditions:
^ A misrouted harness-Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
^ Any unmetered air that enters the engine may cause this DTC to set. Verify that the oil dipstick is fully seated and the oil filler cap is secure.
^ Inspect for any vacuum leaks downstream of the MAF sensor.
^ A wide open throttle acceleration should cause the MAF display to increase from 4-7 g/s at idle to 150 g/s or more during the 1-2 shift. If the change in the display is not observed, inspect for a restriction.
^ The barometric pressure that is used in order to calculate the predicted mass air flow value is based on the Manifold Absolute Pressure (MAP) sensor at key ON. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate. The value shown for the MAP sensor display will vary with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value at or near sea level. The value decreases by approximately 3 kPa for every 305 m (1,000 feet) of altitude.

If you suspect the vehicle condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Diagrams.

If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-5:

Steps 6-14:

Steps 15-24:

The numbers below refer to the step numbers on the diagnostic table.
5. Any unmetered air that enters the engine may cause this DTC to set. This step eliminates the conditions which can cause a DTC to set with a normally operating MAF sensor.
10. This step verifies the signal circuit from the MAF sensor electrical connector to the PCM. A voltage reading of less than 4 volts or greater than 6 volts indicates a malfunction in the wiring or a poor connection.