P04CFEGR Temperature Sensor C Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- 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. The code standard allows up to four EGR temperature sensors, A to D – for example before and after the cooler, or in the high- and low-pressure circuits; which is which depends on the maker. Sensor C is the third of them, usually an NTC whose low voltage means hot. P04CF is its plausibility check: the signal is electrically valid but does not fit the model or other temperatures. Comparable checks on sensors A and B compare it after a long stop with coolant and intake air, or look for a temperature change during EGR operation (Ford diesels, GM diesels above 10 °C). No manufacturer document available to us uses P04CF; FCA lists P040B as the range code for its sensor C part.
- What you may notice
- Check engine light on
- Usually no change in driving (EGR on a substitute value or off)
- Possibly EGR flow or cooler codes (P0401, P2457)
- Likely causes
- LikelySensor drifting or sluggish (soot, ageing)
- PossibleContact resistance at the connector
- PossibleEGR cooler or valve problem changes the real temperature
- RareComparison sensor (coolant, intake air, exhaust) faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.