DTC P0135: 1/1 O2 Sensor Heater Failure: Description

The 1/1 HO2S heater is monitored when battery voltage is more than 9 volts, at a cold start, engine coolant temperature is less than 147°F (64°C), battery temperature is within 27 degrees of engine temperature and engine has been idling for at least 12 seconds. DTC may be stored in Powertrain Control Module (PCM) if 1/1 HO2S voltage is more than 3 volts for 30-90 seconds. Possible causes are:

• Faulty 1/1 HO2S Heater Element
• 1/1 HO2S Heater Ground Circuit Open
• 1/1 Oxygen Sensor Relay Output Circuit Open
• Intermittent Condition
• Faulty PCM