U05A2NOx Sensor B Received Invalid Data From ECM/PCM
- 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
- This is the downstream counterpart of U05A1: the tailpipe NOx sensor B finds the frames it gets from the engine controller missing or implausible and reports it. Ford's 2023 diesel summary documents it for the 3.0 L and 6.7 L engines next to P229E in the tailpipe NOx controller checks, using the same criteria as for the front sensor, an erroneous signal such as a dew point release with ignition off, or more than 1 s without a message, confirmed after 5 s. Ford's 2014 list also shows it with MIL. Because sensor B measures what leaves the SCR catalyst, the efficiency monitor cannot finish while the code is active. U059F describes the reverse problem, U029E a sensor that has gone quiet. A software update or bus repair usually comes before replacing the sensor.
- What you may notice
- Check engine light on
- SCR efficiency monitor incomplete
- Likely causes
- PossibleDamaged harness to the rear sensor, exposed to road spray and heat
- PossibleEngine controller software sending implausible commands
- RareFault inside the sensor B control unit
- 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.