Possible Causes
NOTE:
Monitor description.
The heated oxygen sensor heater duty cycle is at its maximum value but the sensor does not reach operating temperature
- The engine control module has determined failures where some circuit quantity, reported via serial data, is above a specified range
- Heated oxygen sensor circuit short circuit to ground, short circuit to power, open circuit, high resistance
- Connector is disconnected, connector pin is backed out, connector pin corrosion
- Heated oxygen sensor failure