Symptoms of P0406 OBD II Trouble Code
- Increase in combustion temperatures (and NOx emissions)
- MIL (Malfunction indicator lamp) illumination
- Possible surging while driving
- Possible intermittent stall
Common Causes of P0406 OBD II Trouble Code
- EGR sensor signal circuit shorted to B+ (battery voltage)
- EGR sensor signal circuit shorted to the 5 volt reference circuit to EGR
- EGR sensor ground circuit open
- EGR sensor signal circuit open
- Bad EGR (internal failure on EGR sensor or solenoid)
- Debris caught in valve and holding it open or closed