U02A3Lost Communication With Particulate Matter Sensor
- 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 particulate matter sensor behind the diesel particulate filter collects soot on a heated element; its own control unit reports the result over CAN, and the engine controller uses it to judge the filter. U02A3 means those frames have stopped. Ford's 2023 diesel summary sets it after 7 s at 11 to 16 V. GM waits 10 s and rates it Type B. Ford's 2014 code list and FCA's Ram 2500 and 3500 bulletin 18-052-19 show it with MIL. FCA STAR case S2218000023 for the 2019 Jeep Compass explains U02A3 right after a sensor replacement by a wrong sensor variant, so compare the stamped part number. On 2023 Volvo and Mack trucks it set when the engine was cranked immediately after key on; new software followed. The filter check stays incomplete, and on trucks a derate is possible.
- What you may notice
- MIL on
- Particulate filter monitor not completed
- Derate or inducement warning on some trucks
- Likely causes
- LikelyWrong particulate sensor variant fitted during repair
- PossibleChafed harness, blown fuse or corroded connector at the sensor unit
- PossibleEngine control software with start-up timing fault
- RareParticulate sensor control unit internally failed
- 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: €0 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.