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U010A Lost Communication With Exhaust Gas Recirculation Control Module A

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U010A is set when a stand-alone control module for exhaust gas recirculation A stops communicating. J2012 reserves this slot for engines whose EGR valve or EGR system is run by its own electronics on the bus rather than as a plain output of the engine controller; module B (U010B) would be a second such unit. No manufacturer documents U010A publicly, and the NHTSA bulletin index holds no entry for it. Because EGR lowers combustion temperature and NOx, CARB requires it to be monitored, so a lost EGR controller counts as emission-relevant. The nearest documented case is GM's boost control module (U010C), a smart actuator on a sensor bus. Expect EGR shut off and possibly reduced power. U040B covers invalid data.

Likely causes

EGR module A without power or ground
Heat-damaged wiring or connector near the exhaust side
Open or shorted bus lines to module A
EGR module A internally faulty

Symptoms

  • MIL on
  • EGR deactivated, higher NOx
  • Possible reduced power mode

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–900
Time0.5–3 h

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

Parts involved

egr module acan bus wiring

Related codes

U010BU040BU010C

References: law.cornell.edu, en.wikipedia.org.