DTC P0038: A/F/O2 Heater Control Circuit High Bank 1 Sensor 2: Notes

WARNING: This page is about a different variant/trim than selected.

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DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

Wiring diagram:

Engine Electrical System. Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>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) (H4DO (HEV))>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) (H4DO (HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR (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
  
  (B134) No. 22 (+) - Engine ground (-):
  
  Is the voltage 10 V or more?
  
  Yes : Repair the short circuit to power supply in harness between ECM connector and rear oxygen sensor connector.
  
  No : Go to 2.
CHECK GROUND CIRCUIT FOR ECM (OPEN CIRCUIT) .
1. Disconnect the connector from ECM.
2. Measure the resistance between the ECM connector and engine ground.
  Connector & terminal
  
  (B134) No. 69 - Engine ground:
  
  (B134) No. 70 - Engine ground:
  
  (B134) No. 71 - Engine ground:
  
  (B134) No. 72 - Engine ground:
  
  Is the resistance less than 5 Ω?
  
  Yes : Repair the poor contact of ECM connector.
  
  No : Check the harnesses and connectors, and repair or replace them if necessary.
  NOTE:
  In this case, repair the following item:
  - Open circuit of harness between ECM connector and engine ground
  - Poor contact of coupling connector