DTC P0135: Heated Oxygen Sensor No. 1 - Heater Circuit Malfunction: Condition

DTC is set when Engine Control Module (ECM) detects Heated Oxygen Sensor No. 1 (HO2S-1) heater circuit voltage input is less or more than predetermined. MIL is illuminated when ECM detects malfunction during 2 consecutive drive cycles. Possible causes are:

• ECM malfunction.
• HO2S-1 malfunction.
• HO2S-1 heater circuit malfunction.