P0137 OBD Trouble Code

O2 Sensor Circuit Low Voltage

HO2S Shorted to Ground Conditions

Key off, engine cool-down period completed, cold engine startup requirement met (ECT sensor input under 100°F), then the test started and the PCM detected that the rear HO2S-12 signal was less than 156 mv prior to starting the HO2S-12 heater test, or that it was less than 156 mv at next engine startup

HO2S Circuit Low Input Conditions

No PCM codes set, engine running, throttle angle 2-40% for 4.5 minutes and PCM detected the HO2S signal was below 100 mv.