HO2S 2 CIRCUIT VOLTAGE HIGH
Three-Way Catalyst (TWC) system is used to control emissions.
PCM uses signal from Heated Oxygen Sensor (HO2S) behind TWC to read
efficiency of TWC. PCM will set DTC P0137 if TWC oxygen storage
capacity is less than a predetermined threshold.
There may be no noticeable symptoms except for MIL light. Engine might be running rich.
- Faulty O2 sensor
- Short to battery voltage in O2 sensor signal circuit
- High fuel pressure