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U011A Lost Communication With Exhaust Gas Sensor Module A

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

U011A appears when the engine controller loses exhaust gas sensor module A, the electronics that heat and evaluate a wide-band oxygen probe (or a similar exhaust sensor) and send the result as bus data instead of analogue signals. Chrysler's bulletin 25-002-14, which replaces 25-003-13 and 25-004-13, lists it for 2010–2012 Ram 2500/3500 pickups with the 6.7 L Cummins among oxygen-sensor faults; the prescribed fix is an overlay harness with new connectors at the sensor module before any part is changed. Module B has U016D, invalid data from A is U041B. Since the controller loses the oxygen value it needs for combustion and aftertreatment control, the MIL lights and soot-model or regeneration functions may be restricted.

Likely causes

Heat-stressed wiring or poor terminal contact at the sensor module connector
Sensor module without power or ground
Exhaust gas sensor module internally faulty

Symptoms

  • MIL on
  • Further oxygen-sensor codes stored
  • Particulate filter regeneration restricted

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–900
Time1–4 h

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

Parts involved

exhaust gas sensor module acan bus wiring

Related codes

U016DU041BU029DP2626

References: static.nhtsa.gov, law.cornell.edu.