DTC P0045: Turbocharger/Supercharger Boost Control "A" Circuit/Open: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Poor driving performance
Poor acceleration

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 HARNESS BETWEEN ECM AND ELECTRONIC WASTEGATE VALVE CONNECTOR (SHORT TO POWER SUPPLY) .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the voltage between ECM connector and engine ground.
  Connector & terminal
  
  (E159) No. 18 (+) - Engine ground (-):
  
  (E159) No. 26 (+) - Engine ground (-):
Is the voltage 5 V or more?

Yes: Repair the power supply short circuit of harness between ECM connector and electronic wastegate valve connector.

No: Go to 2.
CHECK HARNESS BETWEEN ECM AND ELECTRONIC WASTEGATE VALVE CONNECTOR (OPEN) .
1. Disconnect the connector from electronic wastegate valve.
2. Measure the resistance between ECM connector and electronic wastegate valve connector.
  Connector & terminal
  
  (E159) No. 18 - (E30) No. 6:
  
  (E159) No. 26 - (E30) No. 4:
Is the resistance less than 1 Ω?

Yes: Go to 3.

No: Repair the open circuit in harness between ECM connector and electronic wastegate valve connector.
CHECK HARNESS BETWEEN ECM AND ELECTRONIC WASTEGATE VALVE CONNECTOR (SHORT TO GROUND) .
Measure the resistance between the ECM connector and engine ground.

Connector & terminal

(E159) No. 18 (+) - Engine ground (-):

(E159) No. 26 (+) - Engine ground (-):

Is the resistance 1 MΩ or more?

Yes: Go to 4.

No: Repair the ground short circuit of harness between ECM connector and electronic wastegate valve connector.
CHECK FOR POOR CONTACT .
Check for poor contact in ECM and electronic wastegate valve connector.

Is there poor contact in ECM or electronic wastegate valve connector?

Yes: Repair the poor contact of ECM or electronic wastegate valve connector.

No: Replace the turbocharger. Ref. to INTAKE (INDUCTION) (H4DOTC)>TURBOCHARGER>REMOVAL .