DTC P0033: Turbocharger/Supercharger Bypass Valve "A" Control Circuit: 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 POWER SUPPLY OF ELECTRONIC AIR BY-PASS VALVE .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from electronic air by-pass valve.
3. Turn the ignition switch to ON.
4. Measure the voltage between electronic air by-pass valve connector and engine ground.
  Connector & terminal
  
  (E120) No. 1 (+) - Engine ground (-):
Is the voltage 10 V or more?

Yes: Go to 2.

No: Repair the following item.
- Open circuit or short circuit to ground of harness between M/B and electronic air by-pass valve connector
- Blown out of fuse
- Poor contact of coupling connector
CHECK HARNESS BETWEEN ECM AND ELECTRONIC AIR BY-PASS VALVE CONNECTOR (SHORT TO GROUND) .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance between electronic air by-pass valve connector and engine ground.
  Connector & terminal
  
  (E120) No. 2 - Engine ground:
Is the resistance 1 MΩ or more?

Yes: Go to 3.

No: Repair the ground short circuit of harness between ECM connector and electronic air by-pass valve connector.
CHECK HARNESS BETWEEN ECM AND ELECTRONIC AIR BY-PASS VALVE CONNECTOR (OPEN) .
Measure the resistance of harness between ECM connector and electronic air by-pass valve connector.

Connector & terminal

(E51) No. 9 - (E120) No. 2:

Is the resistance less than 1 Ω?

Yes: Go to 4.

No: Repair the open circuit of harness between ECM connector and electronic air by-pass valve connector.
CHECK FOR POOR CONTACT .
Check for poor contact in ECM and electronic air by-pass valve connector.

Is there poor contact in ECM or electronic air by-pass valve connector?

Yes: Repair the poor contact of ECM or electronic air by-pass valve connector.

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