P0103

DTC P0103 MAF Sensor Circuit High Frequency





Circuit Description
The Mass Air Flow (MAF) sensor measures the amount of air entering the engine during a given time. The VCM uses the Mass Air Flow information for the fuel delivery calculations. A large quantity of air entering the engine indicates an acceleration or a high load situation, while a small quantity of air indicates a deceleration or a idle situation.
The MAF sensor produces a frequency signal which a scan tool can monitor. The frequency varies within a range of around 5 to 7 g/s at idle to near 125 g/s at maximum engine load.

Conditions for Setting the DTC High Frequency Test
- The engine is running.
- Engine Run Time is at least 0.4 seconds.
- System voltage is at least B volts.
- Above conditions present for 0 seconds.

Action Taken When the DTC Sets
- The VCM illuminates the Malfunction Indicator Lamp (MIL) the first time the fault is detected.
- The VCM calculates an airflow value based on the Idle Air Control (IAC) valve position, throttle position, engine speed and barometric pressure.
- The VCM stores the conditions which were present when the DTC set as Freeze Frame and the Fail Records data.

Conditions for Clearing the MIIJDTC
- The VCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.
- A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle).
- Use the scan tool Clear Information function.
- Disconnect the VCM battery feed for 30 seconds.

Diagnostic Aids
Check for the following conditions:
- Poor connection at VCM Inspect harness connectors for the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal to wire connection
- 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 fault.

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.