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

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Poor driving performance
Poor acceleration

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 .

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

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 and terminal.
  
  (E158) No. 39 (+) - Engine ground (-):
  
  (E158) No. 52 (+) - 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 and terminal.
  
  (E158) No. 39 - (E30) No. 6:
  
  (E158) No. 52 - (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 and terminal.

(E158) No. 39 (+) - Engine ground (-):

(E158) No. 52 (+) - 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 .