DTC P0108: Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High: Notes

DTC detecting condition:

Immediately at fault recognition

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>CLEAR MEMORY MODE>OPERATION ., and inspection mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>INSPECTION MODE>PROCEDURE .
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 .

Courtesy of SUBARU OF AMERICA, INC.

CHECK CURRENT DATA .
1. Start the engine.
2. Read the value of «Mani. Absolute Pressure* using the Subaru Select Monitor or a general scan tool.
  NOTE:
  - Subaru Select Monitor
    For detailed operation procedures, Refer to "Current Data Display For Engine". Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Subaru Select Monitor .
  - General scan tool
    For detailed operation procedures, Refer to the general scan tool operation manual.
Is the value of «Mani. Absolute Pressure* 119.5 kPa (896.5 mmHg, 35.29 InHg) 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 again.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
CHECK HARNESS BETWEEN ECM AND MANIFOLD ABSOLUTE PRESSURE SENSOR CONNECTOR .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from manifold absolute pressure sensor.
3. Start the engine.
4. Read the value of «Mani. Absolute Pressure* using the Subaru Select Monitor or a general scan tool.
  NOTE:
  - Subaru Select Monitor
    For detailed operation procedures, Refer to "Current Data Display For Engine". Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Subaru Select Monitor .
  - General scan tool
    For detailed operation procedures, Refer to the general scan tool operation manual.
Is the value of «Mani. Absolute Pressure* 119.5 kPa (896.5 mmHg, 35.29 inHg) or more?

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

No: Go to 3 .
CHECK HARNESS BETWEEN ECM AND MANIFOLD ABSOLUTE PRESSURE SENSOR CONNECTOR .
1. Turn the ignition switch to OFF.
2. Measure the resistance of harness between manifold absolute pressure sensor connector and engine ground.
  Connector & terminal
  
  (E21) No. 1 - Engine ground:
Is the resistance less than 5 Ω?

Yes: Go to 4 .

No: Repair the harness and connector.
NOTE:
In this case, repair the following item:
- Open circuit of harness between ECM connector and manifold absolute pressure sensor connector
- Poor contact of ECM connector
CHECK FOR POOR CONTACT .
Check for poor contact of manifold absolute pressure sensor connector.

Is there poor contact of manifold absolute pressure sensor connector?

Yes: Repair the poor contact of manifold absolute pressure sensor connector.

No: Replace the manifold absolute pressure sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>MANIFOLD ABSOLUTE PRESSURE SENSOR .