Powertrain, generic (extended)

P249E Closed Loop Reductant Injection Control At Limit - Flow Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P249E is the counterpart to P249D: here the SCR feedback has trimmed the dosing down to the lowest correction it is allowed, because more reductant seems to arrive than the NOx reading calls for. GM's 2014 diesel table flags a long-term adaptation factor below 0.41 (Type B); the 2018 table lists the low-side check as a two-trip Type B fault. Ford's 2023 summary uses the same 30 s clip rule as for P249D. A dosing valve that leaks or sticks partly open, overly concentrated fluid, ammonia slip being read by the NOx sensor as NOx, or a sensor that reads too low can all lead here. Ammonia smell at the tailpipe and white deposits around the injector are possible clues; drivability itself is rarely affected.

Likely causes

Dosing valve leaking or sticking partly open
Ammonia slip from an aged or overloaded SCR catalyst seen by the NOx sensor
NOx sensor reading too low
Fluid concentration outside specification

Symptoms

  • Malfunction indicator lamp on
  • Ammonia smell from the exhaust
  • White crystalline deposits at the dosing point

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–900
Time1–3 h

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

Parts involved

reductant injector

Related codes

P249DP249CP20EEP202E

References: gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.