U061BLost Communication With Reductant Level Sensor C
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Level sensor C is a third level input of a reductant system and exists only on layouts with more than one tank or measuring point. No manufacturer publicly documents U061B or explains which part carries the letter C. The code says that this third sensor's digital messages have stopped or keep arriving corrupted, so its reading is treated as unknown. Because CARB counts the reductant supply among the SCR functions an OBD system must watch, and asks for a separate code whenever a digital input stops communicating, the fault is emission-related even if levels A and B still report. Volvo's guide for its CAN-connected truck tank sensor starts with the harness and the pins, looking for damage, corrosion and water, which is also the sensible first step here. P21AD to P21B1 cover the circuit faults of sensor C.
- What you may notice
- Malfunction indicator lamp
- Implausible DEF quantity on the display
- Likely causes
- LikelyDamaged pins, corrosion or water in the connector of sensor C
- PossibleHarness to the additional tank or measuring point damaged
- RareInternal failure of level sensor C
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.