Code No. P0072: Intake Air Temperature Sensor Circuit Low Input




OPERATION




FUNCTION




TROUBLE JUDGMENT


Check Conditions
Judgment Criterion

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSTIC PROCEDURE


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



  • Item 43: Intake air temperature sensor
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. Check Intake air temperature sensor itself.



  • Intake air temperature sensor connector check.
  • Check Intake air temperature sensor itself (Refer to ).

Q. Is the check result normal?

Go to Step 3.
Repair or replace the connector, or replace the air flow sensor.

STEP 3. Perform Voltage measurement at air flow sensor connector.



  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal engine-ECU ATS line and body earth.
OK: 4.5 - 4.9 V

Q. Is the check result normal?

Go to Step 6.
Go to Step 4.

STEP 4. Check harness between air flow sensor connector terminal and engine-ECU connector terminal ATS.



  • Check output line for short circuit.

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. M.U.T.-III data list



  • Item 43: Intake air temperature sensor
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.

STEP 6. Perform resistance measurement at air flow sensor connector.



  • Disconnect connector, and measure at harness side.
  • Resistance between terminal engine-ECU ATSE line and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 8.
Go to Step 7.

STEP 7. Check harness between air flow sensor connector terminal and engine-ECU connector terminal ATSE.



  • Check earthing line for damage.

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 8. Check harness between air flow sensor connector terminal and engine-ECU connector terminal ATS.



  • Check output line for damage.

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.