Code No. P0103: Air Flow Sensor Circuit High Input

OPERATION

Power is supplied by the engine control relay connector terminal to the air flow sensor connector terminal, and the air flow sensor connector terminal is earthed through the engine-ECU connector terminal AFSE&ECBE.
The air flow sensor connector terminal outputs a sensor signal, which is input into the engine-ECU connector terminal AFS.

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 EGR control, etc.

TROUBLE JUDGEMENT

Check Conditions

Battery positive voltage is 8 - 16 V
2 seconds later after the ignition switch has been in "ON" position or the engine has started up.

Judgement Criterion

The air flow sensor output voltage is 4.72 V or more.

FAIL-SAFE AND BACKUP FUNCTION

The control is performed using the previous value.
The DPF regeneration is prohibited.
The throttle valve is opened (Electrical discontinuity).
The EGR control is stopped (fully closed).

PROBABLE CAUSES

Failed air flow sensor
Open/short circuit or harness damage 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 114: 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. Resistance measurement at air flow sensor connector (AFSE&ECBE line).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Measure the resistance between the air flow sensor connector (AFSE&ECBE line) and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Check of open circuit and damage in AFSE&ECBE line between engine-ECU connector and air flow sensor connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

STEP 4. M.U.T.-III data list

Refer to Data List Reference Table .

Item 114: 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 5. M.U.T.-III data list

Refer to Data List Reference Table .

Item 114: 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 6.

STEP 6. Replace the air flow sensor.

After replacing the air flow sensor, re-check the trouble symptoms.

Q. Is the check result normal?

	Check end.

	Replace the engine-ECU.