Powertrain, generic (extended)

P214A SCR NOx Catalyst Inlet Temperature Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P214A reports that the exhaust entering the SCR catalyst was hotter than a calibrated ceiling while no particulate filter regeneration was active. The reading normally comes from the temperature sensor between the filter and the urea mixing section. Heat at this point is a threat to the SCR coating: Navistar's patent US20190232224 states that vanadia sublimates above roughly 550 °C, and 40 CFR 1036.115 obliges heavy-duty engine makers to shield vanadium catalysts from such temperatures. No manufacturer documents P214A publicly; Ram bulletins for the 6.7L Cummins name only the sibling P214D, and Ford flags aftertreatment overheating with P200C/P200E. P214B covers the same fault during regeneration, P214C the outlet side. Typical triggers are fuel or oil in the exhaust, overfuelling or a drifting sensor.

Likely causes

Unburnt fuel or engine oil reaching the exhaust (leaking injector, turbocharger seal)
SCR inlet temperature sensor reading too high or wrongly placed after repair
Overfuelling from injection or air-path faults (boost leak, EGR fault)
Engine control software with outdated temperature model

Symptoms

  • Check engine light on
  • Reduced engine power to limit exhaust temperature
  • Further codes for exhaust temperature or SCR efficiency

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–3,000
Time1–5 h

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

Parts involved

scr catalystexhaust gas temperature sensor

Related codes

P214BP214CP214DP20ECP200CP242B

References: patents.google.com, law.cornell.edu, law.cornell.edu.