DTC P0112 Intake Air Temperature Sensor 1 Circuit Low Bank 1: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Improper idling
• Poor driving performance
  CAUTION:

  • After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
  • Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

1. CHECK CURRENT DATA. 
   1. Start the engine.
   2. Read the value of intake air temperature sensor #11 using the Subaru Select Monitor or a general scan tool.
      NOTE:

      • Subaru Select Monitor

        For detailed procedures, refer to "Data Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Subaru Select Monitor .

      • General scan tool

        For detailed operation procedures, refer to the general scan tool operation manual.

   Is the value in intake air temperature sensor #11 120°C (248°F) or more?

   • Yes  : Go to 2. 
   • No  : Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis.
     NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK HARNESS BETWEEN ECM AND MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR CONNECTOR. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connectors from the mass air flow and intake air temperature sensor.
   3. Disconnect the connector from ECM.
   4. Measure the resistance between ECM and engine ground.

      Connector & terminal 

      (E158) No. 5 - Engine ground:

   Is the resistance 1 MΩ or more?

   • Yes  : Replace the mass air flow and intake air temperature sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>Mass Air Flow and Intake Air Temperature Sensor .
   • No  : Repair the short circuit to ground in harness between ECM and mass air flow and intake air temperature sensor connector.