DTC P0137: 1/2 O2 Sensor Shorted To Ground: Description

HO2S circuit is monitored at a cold start with engine coolant temperature less than 98°F (37°C), ambient/battery temperature within 20°F of engine coolant temperature, and engine coolant temperature more than 160°F (71°C) on previous key off. DTC will set when HO2S voltage is less than .059 volt for 3 seconds after starting engine. Possible causes are: defective 1/2 HO2S, signal circuit shorted to ground or defective PCM.