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U061C Lost Communication With Reductant Temperature Sensor A

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

Reductant temperature sensor A tells the controller how warm the diesel exhaust fluid is. That value decides when tank and line heaters must run, when dosing may begin after a cold start, and the concentration reading relies on it, since it is calculated from how fast sound travels through the fluid. On digital units the temperature element shares a housing with the level or quality measurement; SSI's ultrasonic tank sensor, for example, sends temperature, level and concentration together over J1939. U061C is logged when frames that carry temperature A no longer arrive or fail their checks. No manufacturer publicly documents a threshold or delay for this code. The analog circuit faults of the sensor are P2042 to P2046. In winter, a missing temperature can hold off SCR dosing for longer, so NOx emissions rise.

Likely causes

Connector of the combined DEF tank sensor corroded or loose

Damaged data, supply or ground wire to the sensor

Sensor electronics failed, sometimes after freeze damage

Symptoms

Check engine light
DEF heater or SCR dosing starts late or not at all in cold weather
DEF quality reading unavailable

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€80–1,200

Time0.5–3 h

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

Parts involved

reductant temp sensor asensor wiring

References: ssi-sensors.com, static.nhtsa.gov, law.cornell.edu.