P0142 OBD II Trouble Code 02 Sensor Circuit Malfunction (Bank I Sensor 3)

Detailed information on troubleshooting and repairing a P0142 DTC code which refers to an O2 sensor circuit malfunction on sensor number 3 on bank 1. Also includes links to relevant forum topics on the code.

Symptoms of P0142 OBD II Trouble Code

  • MIL (Malfunction Indicator Lamp) illumination
  • Decrease in MPG
  • Increase in tailpipe emissions

Common Causes of P0142 OBD II Trouble Code

  • Bad O2 sensor
  • Signal shorted to voltage
  • Wiring problems due to contact with exhaust components
  • Holes in exhaust near O2 sensor