U059FInvalid Data Received From NOx Sensor B
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Sensor B is normally the tailpipe NOx sensor behind the SCR catalyst, so its readings decide whether the catalyst efficiency test passes. The code means its CAN frames are present but unusable. GM's 2025 diesel tables run the same counter, protection value and checksum test as for sensor A, here on the post-catalyst signal set, and treat it as Type B. FCA lists it for Ram 3500 to 5500 Cab Chassis trucks with the 6.7 L Cummins: bulletin 18-012-13 (2012) and 18-042-20 (2014, calibration without ammonia delete) reflash the ECM because the light could come on with no hardware fault. U029E means the sensor is missing entirely, U05A2 that sensor B rejects engine data. A stored code blocks the SCR efficiency verdict, so check software before buying a sensor.
- What you may notice
- Check engine light on
- SCR efficiency monitor not completing
- No noticeable change in power
- Likely causes
- LikelyEngine controller calibration known to flag false faults (FCA reflash)
- PossibleControl unit of the downstream NOx sensor damaged
- PossibleChafed wiring or water in the connector near the exhaust
- 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: €100 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.