The mass air flow (MAF) sensor is integrated with the intake air temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition.

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore.

The ECM detects that the MAF sensor signal is not within a predetermined range of the calculated MAF value.

DTC P0101 is a Type B DTC.

DTC P0101 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Signal Generator

1. Engine idling, observe the DTC information with a scan tool. DTC P0101 should not set.
2. Verify the scan tool MAF sensor Hz parameter is between 1,700-2,100 Hz.
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 Fame/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

•	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. Ignition OFF, test for less than 5 Ω between the ground circuit terminal 2 and ground.

⇒	If greater than the specified range, repair the ground circuit for an open/high resistance.

4. Ignition ON, load test for B+ between the ignition voltage circuit terminal 4 and ground.

⇒	If less than the specified range, test the ignition voltage circuit for a short to ground or an open/high resistance.

5. Test for 4.8-5.2 V between the signal circuit terminal 5 and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

6. Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal 5 at the MAF/IAT sensor harness connector. Connect the battery voltage supply to B+, and ground the black lead.
7. Set the J 38522 to the following specifications:

•	Signal switch to 5 V

•	Frequency switch to 5K

•	Duty Cycle switch to Normal

Note: The engine will run rough and may stall.

8. Engine idling, observe the scan tool MAF Sensor Hz parameter. The scan tool MAF Sensor parameter should be between 4,950-5,025 Hz.

⇒	If not within the specified range, replace the ECM.

9. If the circuits test normal, replace the MAF/IAT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.