DTC P0154: 2/1 O2 Sensor Stays At Center: Description

2/1 Heated Oxygen Sensor (HO2S) voltage is monitored with engine running for more than 2 minutes and engine coolant temperature is more than 151°F (66°C). Engine must be in closed loop fuel control mode. DTC will set in Powertrain Control Module (PCM) memory if 2/1 HO2S signal voltage is .35-.58 volt for 30 seconds, then 1.5 volts for 60 seconds. Possible causes are: defective 2/1 HO2S, open or high resistance in sensor ground circuit, open or high resistance in signal circuit, or defective PCM.