What this warning usually means
Most SCR faults come from a NOx sensor, the AdBlue pump/pressure, a blocked injector or a heater failure.
Less often, an exhaust leak, a damaged SCR catalyst or a software issue is to blame.
Can the vehicle still start?
Yes, initially. Check for a countdown in miles or starts — that's how long you have before a restart lockout.
Vehicles that show this message
Any AdBlue diesel: vans, 4x4s, cars, motorhomes and light trucks.
What we check on site
The technician confirms the right repair after testing. Many faults are fixed on site; some need a part ordered. Mobile call-out from £150 minimum. Final cost depends on the vehicle, location, diagnosis and work required.
- Full module scan and freeze-frame data
- Live NOx readings before and after the SCR catalyst
- Pump pressure and dosing quantity tests
- Exhaust leak and wiring inspection
What to send us on WhatsApp
- Registration number
- Postcode or a location pin
- A photo of the exact warning, including any miles remaining
- Fault code if you have one
- Whether the vehicle currently starts
Related fault codes
- P20EE
- P2BAD
- P229F
Keep reading