Network, generic

U030E Software Incompatibility With NOx Sensor B

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

NOx sensor B is usually the downstream sensor after the SCR catalyst, the one whose reading reveals how well the catalyst converts and guides the correction of urea dosing. U030E is stored when its software or calibration identity does not match what the engine controller expects, for instance after a replacement sensor with another part number or a controller update the sensor does not support. Ford's 2014 code interpretation gives U030E the MIL marker, just as for sensor A (U030D). In Ford's 2023 diesel summary sensor B is regarded as lost after about 1 s without frames (U029E), and the 2015 summary also lists invalid data from it (U059F). Without a trusted downstream value the SCR efficiency test cannot run, so readiness stays open; a MIL and, depending on the market, DEF-related warnings follow.

Likely causes

Downstream NOx sensor replaced with a part of another number or software level
Upstream and downstream sensors swapped or coded to the wrong position
Engine controller update requiring a newer sensor version

Symptoms

  • MIL and SCR/emission warning
  • SCR efficiency monitor never completes
  • Possible DEF countdown on some trucks

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–700
Time0.5–2 h

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

Parts involved

nox sensor bcontrol module software

Related codes

U029EU059FU030DP20EE

References: performanceparts.ford.com, fordservicecontent.com, fordservicecontent.com.