DTC P0098: Intake Air Temperature Sensor 2 Circuit High Bank 1: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
Poor driving performance

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK DATA MONITOR.
1. Start the engine.
2. Using the Subaru Select Monitor or a general scan tool, read the value of [Intake Air Temperature (B1-S2)].
  NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .
Is the value of [Intake Air Temperature (B1-S2)] less than -40°C (-40°F)?

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 again.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
CHECK FOR POOR CONTACT.
Check for poor contact of ECM and manifold absolute pressure and intake air temperature sensor connector.

Is there poor contact of ECM or manifold absolute pressure and intake air temperature sensor connector?

Yes : Repair the poor contact of ECM or manifold absolute pressure and intake air temperature sensor connector.

No : Go to 3.
CHECK HARNESS BETWEEN ECM AND MANIFOLD ABSOLUTE PRESSURE AND INTAKE AIR TEMPERATURE SENSOR CONNECTOR (OPEN).
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Disconnect the connector from the manifold absolute pressure and intake air temperature sensor.
4. Measure the resistance of harness between ECM connector and the manifold absolute pressure and intake air temperature sensor connector.
  Connector and terminal.
  
  (E158) No. 22 - (E124) No. 1:
  
  (E158) No. 59 - (E124) No. 2:
Is the resistance less than 1 Ω?

Yes : Go to 4.

No : Repair the following item.
- Open circuit of harness between ECM connector and the manifold absolute pressure and intake air temperature sensor connector
- Poor contact of J/C
CHECK HARNESS BETWEEN ECM AND MANIFOLD ABSOLUTE PRESSURE AND INTAKE AIR TEMPERATURE SENSOR CONNECTOR (SHORT TO POWER SUPPLY).
1. Connect all connectors.
2. Turn the ignition switch to ON.
3. Measure the voltage between ECM connector and engine ground.
  Connector and terminal.
  
  (E158) No. 59 (+) - Engine ground (-):
Is the voltage 5 V or more?

Yes : Repair the short circuit to power in harness between ECM connector and the manifold absolute pressure and intake air temperature sensor connector.

No : Replace the manifold absolute pressure and intake air temperature sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>MANIFOLD ABSOLUTE PRESSURE AND INTAKE AIR TEMPERATURE SENSOR .