How the Volkswagen AdBlue system works
Covers: Crafter, Transporter T6/T6.1, Amarok, Caddy, Golf, Passat and Tiguan TDI.
VW group SCR systems use a tank-mounted pump and heater with the engine ECU running the dosing strategy. Many vehicles also have a DPF and SCR-coated filter, so faults often show in pairs.
Common Volkswagen AdBlue faults we see first
- AdBlue tank heater faults leading to 'AdBlue: no start in X miles'
- P20E9 and P20EE efficiency faults on Crafter and Transporter
- NOx sensor failures on 2.0 TDI engines
- Injector deposits on low-speed delivery work
What we check before quoting
We read the engine ECU and gateway, record part numbers and software, and check for any emissions-related recall before discussing options.
Send us the registration and the exact dashboard message or fault code by WhatsApp. We confirm the ECU type and whether the job is suitable before arranging a visit.
Who this is for
Typical off-road VW work: Amaroks used on private land, Transporters converted to race support and Crafters prepared for export.
Important — legal position
Disabling or removing a working emissions control system on a vehicle used on UK public roads is not lawful and will fail an MOT. This service is only for vehicles used off-road, in competition, on private land or exported. Road-registered vehicles in UK use get diagnosis and repair instead.
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