Code No. P0113: Intake Air Temperature Sensor No. 1 Circuit High Input

OPERATION

A power voltage of 5 V is applied to the intake air temperature sensor No.1 output terminal (terminal No. 2) of air flow sensor connector from the engine-ECU (terminal No. 49).
The power voltage is earthed to the engine-ECU (terminal No. 70) from the intake air temperature sensor No. 1 (terminal No. 1).

FUNCTION

The intake air temperature sensor No. 1 converts the intake air temperature into a voltage and inputs the voltage signal to the engine-ECU.
In response to the signal, the engine-ECU corrects the fuel injection amount, etc.
The intake air temperature sensor No. 1 is a kind of resistor, which has characteristics to reduce its resistance as the intake air temperature rises. Therefore, the sensor output voltage varies with the intake air temperature, and becomes lower as the intake air temperature rises.

TROUBLE JUDGMENT

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.

Judgment Criterion

The air temperature sensor No. 1 output voltage is 4.87 V or more for 0.5 second.

PROBABLE CAUSES

Failed intake air temperature sensor No. 1
Open circuit in intake air temperature sensor No. 1 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 43: Intake air temperature sensor No. 1

OK: At ambient temperature (atmospheric temperature) or equivalent.

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-135 air flow sensor connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace the connector.

STEP 3. Check intake air temperature sensor No. 1 itself.

Check intake air temperature sensor No. 1 itself (Refer to ).

Q. Is the check result normal?

	Go to Step 4 .

	Replace the air flow sensor.

STEP 4. Perform voltage measurement at A-135 air flow sensor No. 1 connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 2 and earth.

OK: 4.5 - 4.9 V

Q. Is the check result normal?

Go to Step 8 .

Go to Step 5 .

STEP 5. Connector check: C-105 engine-ECU connector

Q. Is the check result normal?

Go to Step 6 .

Repair or replace the connector.

STEP 6. Check harness between A-135 (terminal No. 2) air flow sensor connector and C-105 (terminal No. 49) engine-ECU connector.

Check output line for open circuit.

Q. Is the check result normal?

Go to Step 7 .

Repair the damaged harness wire.

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

Item 43: Intake air temperature sensor No. 1

OK: At ambient temperature (atmospheric temperature) or equivalent.

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. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 8. Perform resistance measurement at A-135 air flow sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 1 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 7 .

Go to Step 9 .

STEP 9. Connector check: C-105 engine-ECU connector

Q. Is the check result normal?

Repair or replace the connector.

STEP 10. Check harness between A-135 (terminal No. 1) air flow sensor connector and C-105 (terminal No. 70) engine-ECU connector.

Check earthing line open circuit.

Q. Is the check result normal?

Repair or replace the connector.