Code 28 - Main O2 Sensor CKT (Federal - Rear O2 Sensor)

WARNING: This page is about a different car, the 1995 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: After repairs are completed, perform TROUBLE CODE DETECTION DRIVING PATTERN TEST.

Fig 1: Code 28 Rear Oxygen Sensor Flow Chart (GS300 - Federal) Main O2 Sensor Circuit (Rear O2 Sensor)