P0103
DTC P0103 Mass or Volume Air Flow Circuit High InputCIRCUIT DESCRIPTION
DTC Detection Condition:
The Mass Air Flow (MAF) meter is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information to determine the fuel injection time and provide an appropriate air-fuel ratio. Inside the MAF meter, there is a heated platinum wire exposed to the flow of intake air.
By applying a specific electrical current to the wire, the ECM heats it to a given temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting 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 air flow through the sensor, and the ECM uses it to calculate the intake air volume. The circuit is constructed so that the platinum hot wire and the temperature sensor provide a bridge circuit, and the power transistor is controlled so that the potential of A and B remains equal to maintain the predetermined temperature.
HINT: When DTC P0100, P0102 or P0103 is detected, check the air-flow ratio by selecting DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF on 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 meter or an open or short circuit, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the MAF meter and sets a DTC.
Example:
When the sensor voltage output remains less than 0.2 V or more than 4.9 V and if either the condition continues for more than 3 seconds, the ECM sets a DTC.
If the malfunction has not been repaired successfully, a DTC is set 3 seconds after the engine is started.
Wiring Diagram:
INSPECTION PROCEDURE
Step 1:
Step 2 - 3:
Step 4:
Step 5 - 6:
Step 7:
HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
CHECK FOR INTERMITTENT PROBLEMS
HINT:
Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the hand-held tester when the ECM is in check mode. In check mode, the ECM uses 1trip detection logic, which is more sensitive to malfunctions than normal mode (default) that uses 2trip detection logic.
a. Clear DTCs.
b. Switch the ECM from normal mode to check mode using a hand-held tester.
c. Perform a simulation test.
d. Check and wiggle the harness(es), the connector(s) and terminal(s).