DTC P0103

Circuit Description

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor frequency signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has an ignition 1 voltage circuit, a ground circuit, and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 11,500 Hertz at maximum engine load. DTC P0103 sets if the PCM detects a frequency signal higher than the possible range of a properly operating MAF sensor.

Conditions for Running the DTC

• The engine is running for more than 3 seconds.
• The engine speed is more than 400 RPM.
• The ignition 1 signal is more than 8 volts.

Conditions for Setting the DTC

The PCM detects that the MAF sensor frequency signal is more than 13,500 Hertz for more than 1.2 seconds.

Action Taken When the DTC Sets

• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

• Any water that enters the air intake system that reaches the MAF sensor could cause this DTC to set. The water rapidly cools the hot sensing elements in the sensor causing a false indication of excessive air flow. Inspect the following areas for evidence of water intrusion:
• The air induction system.
• The secondary air injection system (AIR), if equipped.
• A poor connection in the ignition 1 voltage circuit of the MAF sensor can cause a DTC P0103 to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

If the condition is intermittent, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.