P04D1EGR Temperature Sensor C Circuit High
- 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. P04D1 means its signal voltage is above the upper limit – extremely cold, or more often an open sensor, signal or ground line, or a short to 5 V. Besides FCA, GM documents it on the 3.0-litre Duramax LM2 of 2020–21, where it is called EGR temperature sensor 2; if the diagnosis leads to the engine module, module and sensor are replaced together. For sensor B Ford diesels use above 4.95 V.
- 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
- LikelySignal or ground line open, connector off or corroded
- PossibleSensor open internally (element broken)
- RareSignal shorted to 5 V or positive
- RareEngine module input
- 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.