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U010E Lost Communication With Reductant Control Module

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

U010E concerns the reductant control module that runs dosing, pump and heaters of a diesel SCR system with urea solution (DEF/AdBlue). GM's 2017 small-diesel table expects frame $092 and several $4Cx/$4Ex frames on bus B and, after 10 s of silence, records a Type A fault with MIL on the first trip, unless bus B is off (U0074). GM's 2025 central gateway judges its DEF controller differently: messages overdue by 2.5 periods for 6.5 s with battery above 7 V give Type B. For Ram 3500–5500 cab chassis with the 6.7 L Cummins (2012), bulletin 18-012-13 brought ECM software against needless MIL with U010E. Without the module no reductant is dosed, NOx rises and the inducement logic may cap speed. U040F covers invalid data.

Likely causes

Reductant module without power or ground (fuse, relay)
Corroded or wet connector at the tank-mounted module
Damaged bus lines along the frame to the module
Engine controller software setting the code falsely

Symptoms

  • MIL and DEF/AdBlue warning
  • Countdown to speed limit or restart block
  • Further SCR codes such as P20EE

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,500
Time0.5–4 h

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

Parts involved

reductant control modulecan bus wiring

Related codes

U0074U030FU040FU02A2P20EE

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.