DTC P023F: Fuel Pump Secondary Circuit/Open: Notes

DTC detecting condition:

Immediately at fault recognition

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) (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 .

CHECK HIGH-PRESSURE FUEL PUMP .
Check the high-pressure fuel pump. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>HIGH PRESSURE FUEL PUMP>INSPECTION .

Is the check result OK?

Yes: Go to 2.

No: Replace the high-pressure fuel pump. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>HIGH PRESSURE FUEL PUMP .
CHECK HARNESS BETWEEN ECM AND HIGH-PRESSURE FUEL PUMP CONNECTOR (SHORTED BETWEEN LINES) .
1. Disconnect the connector from ECM.
2. Disconnect the connector from high-pressure fuel pump.
3. Measure the resistance of harness between ECM connectors.
  Connector & terminal
  
  (E159) No. 1 - (E159) No. 9:
Is the resistance 1 MΩ or more?

Yes: Go to 3.

No: Repair the short between lines in harness between ECM connector and high-pressure fuel pump connector.
CHECK HARNESS BETWEEN ECM AND HIGH-PRESSURE FUEL PUMP CONNECTOR (OPEN) .
1. Disconnect the connector from ECM.
2. Disconnect the connector from high-pressure fuel pump.
3. Measure the resistance of harness between ECM connector and high-pressure fuel pump connector.
  Connector & terminal
  
  (E159) No. 1 - (E160) No. 1:
  
  (E159) No. 9 - (E160) No. 2:
Is the resistance less than 1 Ω?

Yes: Go to 4.

No: Repair the open circuit in harness between ECM connector and high-pressure fuel pump connector.
CHECK HARNESS BETWEEN ECM AND HIGH-PRESSURE FUEL PUMP CONNECTOR (SHORT TO GROUND) .
Measure the resistance between high-pressure fuel pump connector and engine ground.

Connector & terminal

(E160) No. 1 - Engine ground:

(E160) No. 2 - Engine ground:

Is the resistance 1 MΩ or more?

Yes: Go to 5.

No: Repair the short circuit to ground in harness between ECM connector and high-pressure fuel pump connector.
CHECK HARNESS BETWEEN ECM AND HIGH-PRESSURE FUEL PUMP CONNECTOR (SHORT TO POWER SUPPLY) .
Measure the voltage of harness between ECM connector and engine ground.

Connector & terminal

(E159) No. 1 (+) - Engine ground (-):

(E159) No. 9 (+) - Engine ground (-):

Is the voltage 10 V or more?

Yes: Repair the short circuit to power supply in harness between ECM connector and high-pressure fuel pump connector.

No: Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM) .