Powertrain, generic · Auxiliary emission controls

P04DE Cold Start EGR A Flow Excessive Detected

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. P04DE is the counterpart of P04DD: during an active cold-start strategy the flow of EGR A is too high – the strategy calls for little or limited EGR, but the valve lets more through. CARB requires separate codes for cold-start faults. No manufacturer document available to us uses P04DE; FCA uses the neighbouring code P04DD, so its use there is plausible but not documented. Too much exhaust in a cold engine causes rough running, smoke and in extreme cases stalling.

Likely causes

EGR valve not closing fully (soot, condensate, stuck open)
Position sensor reports a wrong position
Air mass or pressure difference misreading

Symptoms

  • Check engine light on
  • Rough idle after a cold start
  • Smoke or soot after a cold start (diesel), stalling possible

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–1,200
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egr valveegr valve position sensoregr controlengine control module

Related codes

P04DDP0402P042EP04DAP0407

References: law.cornell.edu, static.nhtsa.gov.