Powertrain, generic · Auxiliary emission controls

P04CF EGR Temperature Sensor C Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Sensor drifting or sluggish (soot, ageing)
Contact resistance at the connector
EGR cooler or valve problem changes the real temperature
Comparison sensor (coolant, intake air, exhaust) faulty

Symptoms

  • Check engine light on
  • Usually no change in driving (EGR on a substitute value or off)
  • Possibly EGR flow or cooler codes (P0401, P2457)

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–300
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egr temperature sensor csensor wiringengine control module

Related codes

P04CEP04D0P04D1P04D2P040BP2457

References: law.cornell.edu, fordservicecontent.com.