The mass air flow (MAF) sensor is located in the air intake duct. The MAF sensor is an airflow meter that measures the amount of air that enters the engine. The MAF sensor uses a hot film that is cooled by air flowing past the sensing film as air enters the engine. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required in order to maintain the hot film at a constant temperature. The engine control module (ECM) uses the MAF sensor in order to provide the correct fuel delivery for all operating conditions.

DTC P0101 is a Type B DTC.

DTC P0101 is a Type B DTC.

The following table illustrates the ECM connector locations:

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Intake System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool DTC information. Verify DTCs P0102, or P0103 are not set.

⇒	If DTCs P0102, or P0103 are set refer to DTC P0102 or P0103 for further diagnosis.

2. Engine idling for 1 minute, observe the scan tool DTC information. DTC P0101 should not set.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

1. Inspect for the following conditions:

•	An engine vacuum leak

•	An air leak in the intake air duct between the mass air flow (MAF) sensor and the throttle body

•	A plugged or collapsed intake air duct

•	Objects that block the MAF sensor air inlet

•	An air filter element that is restricted

•	The hydro-carbon absorber in the air cleaner assembly for ruptures or deterioration.

•	A restricted throttle plate or for carbon build-up around the throttle plate

•	An unseated engine oil dip stick

•	A loose or missing engine oil fill cap

•	An over filled crankcase

⇒	If you find any of the above conditions, repair as necessary.

2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
3. Remove the fuse that supplies B+ to circuit terminal X2-36 of the engine control module (ECM).
4. Test for less than 5 ohms of resistance between the low reference circuit terminal 3 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

5. Install the fuse that supplies B+ to circuit terminal X2-36 of the ECM.

Notice: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.

6. Ignition ON, load test for B+ between the ignition voltage circuit terminal 2 and ground.

⇒	If less than the specified range, repair the ignition voltage circuit for an open/high resistance.

Important: The engine control module (ECM) for this engine is not equipped with 5-volt reference DTCs. The 5-volt reference circuits are internally and externally connected at the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.

7. Test for 4.8-5.2 volts between the 5 volt reference circuit terminal 4 and the low reference circuit terminal 3 .

⇒	If less than the specified range, test the 5 volt reference circuit for an open or for a short to ground. If the circuit/connections test normal, replace the ECM.

⇒	If greater than the specified range, test the 5 volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.

8. Test for greater than 80 mA between the 5 volt reference circuit terminal 4 and the low reference circuit terminal 3.

⇒	If less than the specified range, test the 5 volt reference circuit for a high resistance. If the circuit/connections test normal, replace the ECM.

9. Install a 3A fused jumper wire between the 5 volt reference circuit terminal 4 and the signal circuit terminal 5. Verify the scan tool MAF sensor voltage parameter is between 4.8-5.2 volts.

⇒	If not within the specified range, test the signal circuit for a high resistance. If the circuit/connections test normal, replace the ECM.

10. If all circuits/connections test normal, replace the MAF sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.