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 MAF/IAT sensor has the following circuits:

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 frequency varies within a range of near 1,700 Hertz at idle to near 9,500 Hertz at maximum engine load.

P0102

The ECM detects that the MAF Sensor parameter is less than 950 Hz for greater than 5 seconds.

P0103

The ECM detects that the MAF Sensor parameter is more than 14,500 Hz for greater than 5 seconds.

DTCs P0102 and P0103 are Type B DTCs.

DTCs P0102 and P0103 are Type B DTCs.

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

Important: All electrical components and accessories must be turned OFF and allowed to power down.

1. Ignition OFF, disconnect the MAF/IAT harness connector at the MAF/IAT sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms between the ground circuit terminal C and ground.

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

3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

4. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal A and ground.

⇒	If less than the specified range, test the signal circuit terminal A 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.

5. Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal A at the MAF/IAT sensor harness connector. Connect the battery voltage supply to B+, and ground the black lead.
6. Set the J 38522 signal to 5 volts, the Frequency to 5K, and the Duty Cycle to Normal.
7. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,025 Hz.

⇒	If the MAF Sensor parameter is not within the specified range, replace the ECM.

8. If all other circuits test normal, replace the MAF sensor.

To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 to the vehicle as follows:

1. Turn OFF the ignition.
2. Connect the battery voltage supply, and ground the black lead.
3. Connect the red lead to the signal circuit of the MAF sensor.
4. Set the Duty Cycle switch to Normal.
5. Set the Frequency switch to 5 K.
6. Set the Signal switch to 5 V.
7. Start the engine.
8. Observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz.

⇒	If the MAF Sensor parameter is not within the specified range, replace the ECM.

⇒	If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.