P046CEGR Sensor A Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. Which part EGR sensors A and B are depends on the maker: sensor A is usually the position sensor of EGR valve A; GM's Duramax diesels of 2017/18 use sensor B for the coolant temperature sensor at the inlet of the high-pressure EGR cooler, FCA for the position sensor of the low-pressure valve. P046C means the signal of sensor A is electrically valid but implausible. GM's diesels (6.6-litre Duramax LML and others from 2014) set it when the actual valve position deviates from the target by 5 % or more for 8 s, with offset learning completed and at least 11 V (MIL after two trips). Ford uses P0405/P0406/P046D for sensor A instead. EGR is then switched off or limited.
- What you may notice
- Check engine light on
- EGR switched off, possibly higher NOx
- Rarely jerking or lack of power
- Likely causes
- LikelyEGR valve coked and stiff, actual position does not follow
- PossiblePosition sensor worn or offset shifted
- PossibleContact resistance at connector or 5 V supply
- RareValues not relearned after valve replacement
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €150 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.