Faulty EGR temperature sensor C itself, due to internal failure or contamination; Damaged or corroded wiring harness connector at the sensor; Open or short circuit in the sensor signal or ground circuit; Exhaust leaks near the EGR cooler affecting temperature readings; Carbon buildup on the sensor tip insulating it from exhaust flow; Failed EGR cooler causing abnormal temperature fluctuations; Corrosion or water intrusion in the connector causing intermittent signals

DTC codes / P04xx · Auxiliary emission controls / P04CE

P04CEEGR Temperature Sensor C Circuit

Q: What does code P04CE mean?

EGR Temperature Sensor C Circuit. P04CE indicates that the powertrain control module has detected an abnormal signal from the exhaust gas recirculation temperature sensor on circuit C, which is typically the sensor located after the EGR cooler. The computer compares the sensor voltage against expected values and flags this code when the signal falls outside the valid range for a calibrated period.

P04CE indicates that the powertrain control module has detected an abnormal signal from the exhaust gas recirculation temperature sensor on circuit C, which is typically the sensor located after the EGR cooler. The computer compares the sensor voltage against expected values and flags this code when the signal falls outside the valid range for a calibrated period.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Slightly rough idle or hesitation during light acceleration
Reduced fuel economy over time due to incorrect EGR flow calculations
Intermittent stumble or surge while cruising at steady speed
In rare cases, a noticeable decrease in engine power if the EGR system remains open

Common causes, most likely first

Faulty EGR temperature sensor C itself, due to internal failure or contamination
Damaged or corroded wiring harness connector at the sensor
Open or short circuit in the sensor signal or ground circuit
Exhaust leaks near the EGR cooler affecting temperature readings
Carbon buildup on the sensor tip insulating it from exhaust flow
Failed EGR cooler causing abnormal temperature fluctuations
Corrosion or water intrusion in the connector causing intermittent signals

How to diagnose and fix it

Connect a scan tool and record freeze-frame data to see when the code sets
Visually inspect the sensor, connector, and wiring for damage or corrosion
Measure sensor resistance and compare to manufacturer specifications
Check for exhaust leaks around the EGR cooler and sensor mounting
Backprobe the sensor signal circuit to verify voltage changes with temperature
Remove and clean the sensor tip if carbon buildup is present, then retest
Replace the EGR temperature sensor if electrical tests confirm it is out of specification

What the EGR temperature sensor C really does

Circuit C often refers to the sensor after the EGR cooler, so a code for this circuit does not always mean the sensor itself has failed; exhaust leaks or cooler issues can skew readings.
Carbon fouling on the sensor tip is a common cause that many technicians miss because the sensor still passes a basic resistance test when cold.
Intermittent codes often trace to a chafed wire near the EGR cooler where heat and vibration damage the insulation over time.
A stuck-open EGR valve can cause temperature readings that mimic a sensor fault, so always check EGR valve operation before replacing the sensor.
Some vehicles use a single sensor for multiple circuits, and a failure in one circuit can set related codes that point away from the true root cause.

Can I keep driving with P04CE?

You can generally continue driving with this code because it rarely causes immediate safety or performance issues, but avoid prolonged idling and schedule a diagnosis soon to prevent potential EGR system damage or increased emissions.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.