OBD-II code · Powertrain (generic)
P04D1 EGR Temperature Sensor C Circuit High
Same as P04CE with the signal voltage above the plausible range. 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 P04D1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to supply
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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 C
Related codes
- P040DEGR Temperature Sensor A Circuit High
- P041DEGR Temperature Sensor B Circuit High
- P04E8EGR Temperature Sensor D Circuit High
- P04CEEGR Temperature Sensor C Circuit
- P04CFEGR Temperature Sensor C Circuit Range or Performance
- P04D0EGR Temperature Sensor C Circuit Low
- P04D2EGR Temperature Sensor C Circuit Intermittent or Erratic
- P04D3Exhaust Brake Input Circuit
- P04D4Exhaust Brake Input Circuit Range or Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.