P0103
DTC P0102 or P0103
DTC Descriptors
DTC P0102
- Mass Air Flow (MAF) Sensor Circuit Low Frequency
DTC P0103
- Mass Air Flow (MAF) Sensor Circuit High Frequency
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
Circuit/System Description
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The control module 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 sensor has the following circuits:
* An ignition 1 voltage circuit
* A ground circuit
* A signal circuit
The control module applies a voltage to the sensor on the 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 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load.
Conditions for Running the DTC
* The engine is cranking or running.
* The engine speed is more than 50 RPM.
* The ignition 1 signal is more than 8 volts.
* The throttle position (TP) indicated angle parameter is more than 3.5 percent.
* The above conditions are met for more than 0.5 second.
Conditions for Setting the DTC
P0102
The control module detects that the MAF sensor frequency signal is less than 1,200 Hertz for more than 10 seconds.
P0103
The control module detects that the MAF sensor frequency signal is more than 11,500 Hertz for more than 10 seconds.
Action Taken When the DTC Sets
DTC P0102 and P0103 are Type B DTCs
Conditions for Clearing the DTC
DTC P0102 and P0103 are Type B DTCs
Diagnostic Aids
* Inspect the harness of the MAF sensor 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
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 3-10 g/s at idle to 150 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* A high resistance may cause a driveability concern before this DTC sets.
Special Tools Required
J 38522 Variable Signal Generator
Circuit/System Testing
1. Inspect for any contamination, water intrusion, or debris on the sensing elements of the MAF sensor.
^ If debris is present, clean the sensor. If the sensor cannot be cleaned, replace the sensor.
2. Ignition OFF, disconnect the harness connector at the MAF sensor.
3. Test for less than 5 ohms of resistance between the ground circuit terminal C and ground.
^ If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the ignition 1 circuit terminal B and ground.
^ If the test lamp does not illuminate, test the ignition 1 circuit for a short to ground or an open/high resistance. If the circuit test normal and the fuse for the ignition 1 voltage circuit is open, test or replace the MAF sensor.
5. 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 for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module.
^ If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the control module.
Important: To set up the J 38522, place the duty cycle to normal, the frequency to 5 K, and the signal switch to 5 volts.
6. Turn OFF the ignition and connect the red lead forth J 38522 to the signal circuit at the MAF sensor harness connector and the black lead to a good ground.
7. Start the engine and observe the MAF sensor for 4,950-5,025 Hz with a scan tool.
^ If the MAF sensor is not within the specified range, test for intermittent or poor connection at the control module. If circuit tests normal, replace the control module.
^ If the MAF sensor is within the specified range, test for intermittent or poor connection at the MAF sensor. If tests normal, replace the MAF sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Mass Airflow Sensor/Intake Air Temperature Sensor Replacement
* Refer to Programming and Relearning for setup, and Programming. Programming and Relearning