Code No. P0103: Air Flow Sensor Circuit High Input

OPERATION

Power is supplied by the engine control relay (terminal No. 2) to the air flow sensor (terminal No. 2), and the air flow sensor (terminal No. 4) is earthed through the engine-ECU (terminal No. 88).
The air flow sensor (terminal No. 3) outputs a sensor signal, which is input into the engine-ECU (terminal No. 87).

FUNCTION

The air flow sensor outputs pulse signal that varies in accordance with the intake air volume.
In response to the signal, the engine-ECU controls exhaust gas recirculation control, etc.

TROUBLE JUDGMENT

Check Condition

3 seconds or more have passed since the ignition switch was turned to "ON" position.

Judgement Criterion

Air flow sensor output voltage is more than 4.9 V (corresponding to an air flow rate of 340 g/sec or more) for 2 seconds.

PROBABLE CAUSES

Failed air flow sensor
Open circuit in air flow sensor circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Refer to Data List Reference Table .

Item 10: Air flow sensor

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2 .

STEP 2. Connector check: A-08 air flow sensor connector

Q. Is the check result normal?

	Go to Step 3 .

	Repair or replace the connector.

STEP 3. Perform resistance measurement at A-08 air flow sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 4 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 7 .

	Go to Step 4 .

STEP 4. Connector check: B-30 engine-ECU connector

Q. Is the check result normal?

	Go to Step 5 .

	Repair or replace the connector.

STEP 5. Check harness between A-08 (terminal No. 4) air flow sensor connector and B-30 (terminal No. 88) engine-ECU connector.

Check earthing line for open circuit.

Q. Is the check result normal?

	Go to Step 6 .

	Repair the damaged harness wire.

STEP 6. M.U.T.-III data list

Refer to Data List Reference Table .

Item 10: Air flow sensor

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the engine-ECU.

STEP 7. M.U.T.-III data list

Refer to Data List Reference Table .

Item 10: Air flow sensor

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the air flow sensor.