DTC P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1): Notes

DTC DETECTING CONDITION:

Immediately at fault recognition

CAUTION: After servicing or replacing faulty parts, perform Clear Memory Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO) > Clear Memory Mode > OPERATION , and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO) > Inspection Mode > PROCEDURE .

WIRING DIAGRAM:

Engine Electrical System NON-TURBO MODEL (WITHOUT PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System > NON-TURBO MODEL (WITHOUT PUSH BUTTON START) .
Engine Electrical System NON-TURBO MODEL (WITH PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System > NON-TURBO MODEL (WITH PUSH BUTTON START) .

Fig 1: Engine Electrical System Non-Turbo Model Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR .
1. Turn the ignition switch to OFF.
2. Disconnect the connectors from ECM and front oxygen (A/F) sensor.
3. Measure the resistance of harness between ECM connector and front oxygen (A/F) sensor connector.
  Connector & terminal
  
  (B136) No. 19 - (E24) No. 3:
  
  (B136) No. 18 - (E24) No. 4:
Is the resistance less than 1 Ω?

Yes: Go to 2 .

No: Repair the harness and connector.
NOTE:
In this case, repair the following item:
- Open circuit in harness between ECM connector and front oxygen (A/F) sensor connector
- Poor contact of coupling connector
CHECK FOR POOR CONTACT .
Check for poor contact of ECM and front oxygen (A/F) sensor connector.

Is there poor contact of ECM or front oxygen (A/F) sensor connector?

Yes: Repair the poor contact of ECM or front oxygen (A/F) sensor connector.

No: Replace the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO) > FRONT OXYGEN (A/F) SENSOR .