DTC P1193: Fuel Rail Pressure Sensor "B" Circuit High: Notes

1. -

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
Poor driving performance

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>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) (H4DO)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

CHECK DATA MONITOR.
1. Start the engine.
2. Using the Subaru Select Monitor, read the value in [Fuel Rail Pressure B].
  NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .
Is the value of [Fuel Rail Pressure B] 0 kPa (0 psi)?

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 FUEL PRESSURE SENSOR POWER SUPPLY.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the fuel pressure sensor.
3. Turn the ignition switch to ON.
4. Measure the voltage between fuel pressure sensor connector and engine ground.
  Connector & terminal
  
  (E162) No. 4 (+) - Chassis ground (-):
Is the voltage 4.5 - 5.5 V?

Yes: Go to 3.

No: Go to 5.
CHECK HARNESS BETWEEN ECM AND FUEL PRESSURE SENSOR CONNECTOR (OPEN).
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance of harness between ECM connector and fuel pressure sensor connector.
  Connector & terminal
  
  (E158) No. 50 - (E162) No. 1:
  
  (E158) No. 58 - (E162) No. 2:
Is the resistance less than 1 Ω?

Yes: Go to 4.

No: Repair the open circuit in harness between ECM connector and fuel pressure sensor connector.
CHECK HARNESS BETWEEN ECM AND FUEL PRESSURE 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 fuel pressure sensor connector and engine ground.
  Connector & terminal
  
  (E158) No. 50 (+) - Engine ground (-):
  
  (E162) No. 1 (+) - Engine ground (-):
Is the voltage 5 V or more?

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

No: Replace the fuel pressure sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>FUEL PRESSURE SENSOR .
CHECK HARNESS BETWEEN ECM AND FUEL PRESSURE SENSOR
CONNECTOR (OPEN).
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance of harness between ECM connector and fuel pressure sensor connector.
  Connector & terminal
  
  (E158) No. 41 - (E162) No. 4:
Is the resistance less than 1 Ω?

Yes: Go to 6.

No: Repair the open circuit in harness between ECM connector and fuel pressure sensor connector.
CHECK HARNESS BETWEEN ECM AND FUEL PRESSURE SENSOR CONNECTOR (SHORT TO GROUND).
1. Measure the resistance between ECM connector and fuel pressure sensor connector and engine ground.
  Connector & terminal
  
  (E158) No. 41 (+) - Engine ground (-):
  
  (E162) No. 4 (+) - Engine ground (-):
Is the resistance 1 MΩ or more?

Yes: Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) .

No: Repair the ground short circuit of harness between ECM connector and fuel pressure sensor connector.