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U030C Software Incompatibility With Reductant Quality Module

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The reductant quality module tells the SCR system whether the tank holds proper urea solution (DEF/AdBlue); in many trucks it sits in the tank unit together with level and temperature sensing. U030C means the engine or dosing controller has rejected its software or calibration, as after a tank or sensor replacement with the wrong part number. Ford's 2014 code interpretation flags U030C as a MIL code; Ford's 2023 diesel summary calls the module RDQM and treats 5 s without its frames as lost communication (U02A2). CARB lets makers skip a direct reductant quality monitor only if an inducement strategy prevents long operation on poor fluid and its inputs, such as this sensor, are monitored themselves. Hence a MIL, DEF warnings and, if left unresolved, speed limits. U05A3 covers invalid data.

Likely causes

DEF tank unit or quality sensor of a different part number installed
Engine or dosing controller updated, quality module left on old software
Programming interrupted or wrong file loaded

Symptoms

  • MIL and DEF/AdBlue system warning
  • Countdown to speed limitation or no-restart shown
  • Code appears after tank, heater or sensor replacement

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–1,200
Time0.5–3 h

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

Parts involved

reductant quality modulecontrol module software

Related codes

U02A2U05A3U030FP2BA9

References: performanceparts.ford.com, fordservicecontent.com, law.cornell.edu.