P0166 OBD II Trouble Code 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 3)

Detailed information on troubleshooting and repairing a P0166 DTC code which refers to the O2 sensor circuit with no detected activity.

Symptoms of P0166 OBD II Trouble Code

  • MIL (Malfunction Indicator Lamp) on
  • May idle or drive poorly
  • Fuel economy may decrease

Common Causes of P0166 OBD II Trouble Code

  • Bad Bank 2, position 3, o2 sensor
  • Wiring problem, melted harness, broken connectors, etc.
  • Bad PCM