OBD-II code · Powertrain (generic)
P04E9 EGR Temperature Sensor D Circuit Intermittent or Erratic
Same as P04D2 on EGR temperature sensor D. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
Is it safe to drive with P04E9?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIntermittent contact at connector
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.6–1.6 h
- Emissions test
- Likely to fail
- Parts involved
- Egr Temperature Sensor D, Egr Temperature Wiring D
Related codes
- P04D2EGR Temperature Sensor C Circuit Intermittent or Erratic
- P04E6EGR Temperature Sensor D Circuit Range or Performance
- P04E7EGR Temperature Sensor D Circuit Low
- P04E8EGR Temperature Sensor D Circuit High
- P04EAEVAP System Small Leak Detected Fuel Tank Side
- P04EBEVAP System Small Leak Detected Fresh Air Side
- P04ECEVAP System Large Leak Detected Fuel Tank Side
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.