P0040 OBD II Trouble Code O2 Sensor Signals Swapped Bank 1 Bank 2 Sensor 1

Symptoms of P0040 OBD II Trouble Code

  • Malfunction indicator lamp (MIL) illuminated solid or flashing
  • Decreased engine power and possible limp mode
  • Increased fuel consumption
  • Rough idle or rough running

Common Causes of P0040 OBD II Trouble Code

  • Oxygen sensor wiring connectors swapped from bank to bank (most likely)
  • O2 sensor wiring crossed, damaged, and/or shorted
  • Failed PCM (less likely)