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OBD-II · Engine and powertrain (P)

P2BA9

NOx exceedance - insufficient AdBlue quality

What it means

NOx emissions may exceed limits because the AdBlue quality is judged too poor. On vehicles with SCR, a confirmed unresolved fault may trigger reduced performance or a no-restart countdown; follow the displayed warning and the vehicle handbook.

Symptoms

  • emissions warning; an AdBlue no-start countdown may appear on SCR-equipped vehicles
  • engine warning light
  • if a no-start countdown is displayed, restarting is inhibited when it reaches zero

Likely causes, most likely first

Likely causes, most likely first
No.Cause
01diluted, contaminated or old AdBlue
02wrong fluid added to the AdBlue tank
03faulty quality sensor
04blocked dosing injector making real dosing too low

What to check, step by step

  1. 01Test the fluid with a refractometer (about 32.5% urea).
  2. 02Drain, flush and refill with fresh AdBlue if poor.
  3. 03Inspect the dosing injector.
  4. 04Run the quality test/relearn with a diagnostic tool if required.