DTC P0134: Heated Oxygen Sensor No. 1 Circuit No Activity Detected: Condition

DTC is set when HO2S No. 1 output voltage is to high or to low when vehicle is at normal operating temperature and is not operating under high load or high engine speed conditions. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• Short or open circuit between HO2S No. 1 and PCM.
• HO2S No. 1 malfunction.
• Fuel system malfunction.
• Exhaust system leak.