DTC P0134 A/F/O2 Sensor Circuit No Activity Detected Bank 1 Sensor 1: Notes

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

DTC detecting condition:

Immediately at fault recognition

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Inspection Mode .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Fig 1: A/F/O2 Sensor Circuit No Activity Detected Bank 1 Sensor 1 - Wiring Diagram

G11272679

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 front oxygen (A/F) sensor.
3. Disconnect the connector from ECM.
4. Measure the resistance of harness between ECM connector and front oxygen (A/F) sensor connector.
Connector & terminal

(B135) No. 57 - (E24) No. 3:

(B135) No. 33 - (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 .