Diagnostic Procedure

WARNING: This page is about a different car, the 2003 GMC Envoy XL and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: DTC P0135, P0141, P0155 & P0161: HO2S Heater Circuit - Banks 1 & 2, Sensors 1 & 2 (Steps 1-6)

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P0135, P0141, P0155 & P0161: HO2S Heater Circuit - Banks 1 & 2, Sensors 1 & 2 (Steps 7-17)

Courtesy of GENERAL MOTORS CORP.

Fig 3: DTC P0135, P0141, P0155 & P0161: HO2S Heater Circuit - Banks 1 & 2, Sensors 1 & 2 (Steps 18-21)

Courtesy of GENERAL MOTORS CORP.