U02A2Lost Communication With Reductant Quality Module
- 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
- The reductant quality module tells the engine or dosing controller whether the tank holds proper diesel exhaust fluid; in many trucks it is one tank sensor unit with level and temperature. U02A2 means its messages have stopped. Ford's 2023 diesel summary allows 5 s without them. In TSB 19-2315 Ford blames water in connectors C3613 and C4851 of the reductant harness on the 6.7 L F-Super Duty of model years 2017-2019 and replaces harness, pump and heater assembly or tank. Hino's SB-15-030 for 2014 and 2015 trucks points to a faulty DEF tank sensor assembly and supplies a more robust one. Mack lists software faults, missing supply and the connector. CARB 1968.2 requires every input of the inducement strategy to be monitored, so the warning sequence that leads to a speed limit may begin.
- What you may notice
- MIL and DEF system warning
- Countdown to speed or restart limitation
- DEF quality and level readings missing
- Likely causes
- LikelyWater in the reductant harness connectors at tank or pump
- PossibleDefective DEF tank sensor unit with quality sensor
- PossibleMissing supply voltage or wrong software version of the module
- RareDamaged CAN wiring between tank sensor and controller
- 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: €50 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.