P0101

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 a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or a 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 the inlet air flow through the sensor bore. The PCM uses the Manifold Absolute Pressure (MAP), the Intake Air Temperature (IAT), 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. Diagnostic Trouble Code (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, P1111, P1112, P1120, P1121, P1122, P1220, or P1221 are not set.
^ The engine is running.
^ The ignition 1 signal is between 11 and 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 Manifold Absolute Pressure (MAP) sensor is less than 80 kPa.
^ The MAP sensor is steady within a range of 3 kPa.
^ The above conditions exist 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 exists for 8 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
Inspect for the following conditions:
^ A misrouted harness-Inspect the MAF sensor harness in order to ensure that the harness is not routed too closely to the following components:
- Any secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
^ The throttle plate sticking, or excessive deposits on the throttle plate, or in the throttle bore.
^ Any unmetered air entering the engine may cause this DTC to set. Verify that the oil dipstick is fully seated and the oil fill cap is secure.
^ A Wide Open Throttle (WOT) acceleration from a stop should cause the MAF value displayed on a scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or more, at the time of the 1-2 shift. If not, inspect for a restriction.

If there is an 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.
2. Diagnose any MAF, MAP, TP or system voltage DTCs before using this table. If a misfire condition exists or a rough running condition is observed with or without DTC P0300 set, proceed to DTC P0300 first.
5. Any unmetered air entering the engine may cause this DTC to set. This step eliminates any 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 more than 6 volts indicates a malfunction in the wiring or a faulty connection.