P1143

BZ: DTC P1143 - PRESSURE SENSOR CIRCUIT RANGE/PERFORMANCE PROBLEM (LOW INPUT)

DTC DETECTING CONDITION:
- Two consecutive driving cycles with fault

CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY and INSPECTION MODES. Clearing Diagnostic Trouble Codes





WIRING DIAGRAM

10BZ1: CHECK IDLE SWITCH SIGNAL.
1) Turn ignition switch to OFF.





2) Connect Subaru Select Monitor to data link connector.

3) Turn ignition switch to ON and Subaru Select Monitor switch to ON.

4) Operate the LED operation mode for engine using Subaru Select Monitor.

NOTE:
- Subaru Select Monitor
For detailed operation procedure, refer to the "LED OPERATION MODE FOR ENGINE".

CHECK: Does the LED of (idle Switch Signal) come on?

YES: Go to step 10BZ2.

NO: Check throttle position sensor circuit.

NOTE:
In this case, it is not necessary to inspect DTC P1143.

10BZ2: CHECK DATA FOR CONTROL.
1) Turn ignition switch to OFF.





2) Connect Subaru Select Monitor or the OBD-II general scan tool to data link connector.

3) Turn ignition switch ON and Subaru Select Monitor or the OBD-II general scan tool switch ON.

4) Start engine.

5) Read data of atmospheric absolute pressure signal using Subaru Select Monitor or OBD-II general scan tool.

NOTE:
- Subaru Select Monitor
For detailed operation procedure, refer to the "READ CURRENT DATA SHOWN ON DISPLAY FOR ENGINE".
- OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II General Scan Tool Instruction Manual.

CHECK: Is the value less than 32 kPa (240 mmHg, 9.45 inHg)?

YES: Go to step 10BZ4.

NO: Go to step 10BZ3.

10BZ3: CHECK PRESSURE SENSOR.
1) Measure actual atmospheric pressure.

2) Read data of atmospheric absolute pressure signal using Subaru Select Monitor or OBD-II general scan tool.

NOTE:
- Subaru Select Monitor
For detailed operation procedure, refer to the "READ CURRENT DATA SHOWN ON DISPLAY FOR ENGINE".

CHECK: Is the difference between absolute value of Subaru Selector Monitor indication and actual atmospheric pressure greater than 10 kPa (75 mmHg, 2.95 inHg)?

YES: Replace pressure sensor.

NO: Even if MIL lights up, the circuit has returned to a normal condition at this time. Contact with Subaru of America (SOA) service.

NOTE:
Inspection by Subaru of America's DTM is required, because probable cause is deterioration of multiple parts.

10BZ4: CHECK VACUUM HOSES.





Check the following item. Incorrect hose connections in line between the pressure sources switching solenoid valve and pressure sensor~ intake manifold and/or purge control solenoid valve.

CHECK: Is there a fault in vacuum hose?

YES: Repair or replace hoses or filter.

NO: Go to step 10BZ5.

10BZ5: CHECK PRESSURE SOURCES SWITCHING SOLENOID VALVE.
1) Turn ignition switch to OFF.





2) Connect test mode connector.

3) Turn ignition switch to ON.

NOTE:
Pressure sources switching solenoid valve operation check can also be executed using Subaru Select Monitor. For the procedure, refer to the "COMPULSORY VALVE OPERATION CHECK MODE".

CHECK: Does pressure sources switching solenoid valve produce operation sound? (ON <-> OFF each 1.5 sec.).

YES: Replace pressure sensor.

NO: Replace pressure sources switching solenoid valve.