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 and terminal.
  
  (E29) 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 BYPASS 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 and terminal.
  
  (E29) 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 BYPASS VALVE CONNECTOR (OPEN).
Measure the resistance between ECM connector and electronic air by-pass valve connector.

Connector and terminal.

(E158) No. 12 - (E29) 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>REMOVAL .