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

Engine Electrical System ENGINE TYPE EZ (WITHOUT PUSH BUTTON START) <Ref. to ENGINE PERFORMANCE (Legacy), ENGINE PERFORMANCE (Outback), Engine Electrical System.>
Engine Electrical System ENGINE TYPE EZ (WITH PUSH BUTTON START) <Ref. to ENGINE PERFORMANCE (Legacy), ENGINE PERFORMANCE (Outback), Engine Electrical System.>

Fig 1: Engine Electrical System - Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from ECM and front oxygen (A/F) sensor. Measure the resistance of harness between ECM connector and front oxygen (A/F) sensor connector. Connector & terminal (E158) No. 46 - (E47) No. 3: (E158) No. 33 - (E47) No. 4:	Is the resistance less than 1 Ω?	Go to step 2.	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
2 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?	Repair the poor contact of ECM or front oxygen (A/F) sensor connector.	Replace the front oxygen (A/F) sensor. <Ref. to FRONT OXYGEN (A/F) SENSOR .>