P0103
DTC P0103 Mass Air Flow (MAF) Sensor Circuit High Frequency
Circuit Description
The mass air flow (MAF) sensor is an air flow meter. The controls module (PCM/VCM) supplies the MAF sensor a signal circuit. An ignition voltage is supplied to the MAF sensor by an independent circuit. A ground is supplied to the MAF sensor by an independent circuit. The MAF sensor heats a wire element, or grid, within the MAF sensor in order to a calculated temperature. As inlet air flows across and cools the grid, the MAF sensor increases current flow to the grid in order to maintain a constant grid temperature. The MAF sensor converts the grid current flow into a frequency signal. The controls module converts the MAF signal frequency into a grams per second value. During low air flow rates, such as at engine idle, the MAF sensor produces a low frequency signal. During high air flow rates, such as wide open throttle-road load, the MAF sensor increases the frequency signal. The controls module monitors the MAF sensor signal frequency to calculate the flow and mass of the air entering the engine.
This DTC is designed to detect an unusually high MAF sensor signal frequency. If the VCM detects a MAF signal frequency above the possible range of a normally operating MAF sensor, this DTC will be set.
Conditions for Running the DTC
- The engine is running.
- The engine speed is more than 300 RPM.
- The system voltage is more than 8 volts.
Conditions for Setting the DTC
The MAF frequency is 11000 Hz or more for more than 1 second.
Action Taken When the DTC Sets
- The control module illuminates the malfunction indicator lamp (MIL) if a failure is detected during 2 consecutive key cycles.
- The control module sets the DTC and records the operating conditions at the time the diagnostic failed. The failure information is stored in the scan tool's Freeze Frame and Failure Records.
Conditions for Clearing the MIL/DTC
- The control module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed
- A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm up cycle occurs when the coolant temperature has risen 22° C (40° F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70° C (158° F) during the same ignition cycle.
- Use the scan tool Clear Information function
Diagnostic Aids
Check for the following conditions:
- A misrouted harness. Inspect the MAF sensor harness in order to ensure that it is not routed too close to the high voltage wires such as spark plug leads.
- A damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving connectors and wiring harnesses related to the MAF sensor. A change in the display will indicate the location of the malfunction.
An intermittent may be caused by any of the following conditions:
- A poor connection
- Rubbed through wire insulation
- A broken wire inside the insulation
Thoroughly check any circuitry that is suspected of causing the intermittent complaint Refer to Testing for Intermittent and Poor Connections.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs.
Steps 1 - 2:
Steps 3 - 6:
Steps 7 - 10:
Step 11:
Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. This step verifies that the problem is present at idle.
4. A frequency reading with the MAF sensor connector disconnected indicates an Electromagnetic Interference (EMI) related fault or a poor connection. Disconnecting the MAF sensor may set additional related DTCs.