P2BAD: NOx exceedance – root cause unknown

What does it mean?

System

Powertrain (engine and transmission)

Type of code

Generic code: means the same on every make.

How urgent?

Have it checked soon. You can usually still drive, but avoid long trips and heavy loads.

Possible causes

• Poor-quality or nearly empty AdBlue
• Blocked AdBlue injector or crystals in the line
• NOx sensor before or after the SCR catalyst
• AdBlue pump, heater or control module

Tip: don’t just clear the code. Clearing a code doesn’t fix the cause. It often comes back, and the stored data that helps us find the cause is then gone.