Troubleshooting

DTC P0103 Mass or Volume Air Flow Circuit High Input

CIRCUIT DESCRIPTION

DTC Detection Condition:

The MAF (Mass Air-Flow) meter measures the amount of air flowing through the throttle valve. The ECM uses this information to determine the fuel injection time and provide a proper air-fuel ratio. Inside the MAF meter, there is a heated platinum wire exposed to the flow of intake air.

By applying a specific current to the wire, the ECM heats this wire to a given temperature. The flow of incoming air cools the wire and an internal thermistor, changing their resistance. To maintain a constant current value, the ECM varies the voltage applied to these components in the MAF meter. The voltage level is proportional to the airflow through the sensor and the ECM interprets this voltage as the intake air amount.

The circuit is constructed so that the platinum hot wire and the temperature sensor provides a bridge circuit, with the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.

HINT: After confirming DTC P0100, P0102 or P0103, confirm the mass air flow ratio in the "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL" using the hand-held tester or the OBD II scan tool.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Component Operating Range:

If there is a defect in the MAF (Mass Air Flow) meter or an open or short circuit, the voltage level will deviate outside the normal operating range. The ECM interprets this deviation as a defect in the MAF meter and sets a DTC.

Example:
When the MAF meter voltage output is less than 0.2 V, or more than 4.9 V, and if either the condition continues for more than 3 sec.

Wiring Diagram:

Step 1 - 2:

Step 3 - 5:

Step 6 - 7:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, as well as other data from the when a the malfunction occurred.

CHECK FOR INTERMITTENT PROBLEMS

Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in check mode with hand-held tester. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.

a. Clear the DTCs.
b. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and connector.