P04E9EGR Temperature Sensor D Circuit Intermittent/Erratic
- 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. Sensor D is the fourth of up to four EGR temperature sensors, conceivable on engines with high- and low-pressure EGR and a sensor before and after each cooler; it is usually an NTC whose low voltage means hot. No manufacturer document available to us uses sensor D; the description follows CARB and Ford's checks on sensor B as a comparison. P04E9 means the signal briefly leaves its valid range or changes impossibly fast – typically a loose contact. Ford detects such sporadic faults on other sensors with short limit violations of about 0.4 s.
- What you may notice
- Check engine light on, may come and go
- Usually no change in driving
- Likely causes
- LikelyLoose contact in connector or harness (vibration, heat)
- PossibleSensor with an internal hairline crack
- PossibleChafed harness
- RareModule or ground connection
- 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: €40 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.