vinkodex.AdBlue / SCR: NOx sensor and crystallising dosing valve
Typically between 100,000 and 160,000 km. It does not show up on every car.
expensive
severity
between 100,000 and 160,000 km
mileage
3
sources
3 sources next to the write-up.
The fault
How you spot it
On AdBlue (SCR) diesels the NOx sensor after the catalyst ages, and the tip of the dosing valve crystallises. An AdBlue warning appears on the dash, often with a countdown ("X km of starts remaining"), while the tank is full. Crystallisation typically forms with short trip, urban use, or from poor quality AdBlue; on a car standing below freezing the circuit can freeze up too.
At the end of the countdown there is a start inhibit: the car can become undriveable until it is repaired. The fault is not always the SCR catalyst: the cause is the sensor or the dosing valve.
Which model
Who it affects
The card opens the generation, the engine or the transmission.
Engines and transmissions
Engine
CLHB
Engine
CRKA
Engine
CUTA
Engine
CUUC
Engine
CUUD
Engine
CUUE
Engine
CUUF
Engine
CUVB
Engine
CXEB
Engine
CXEC
Engine
CXFA
Engine
CXGA
Engine
CXGB
Engine
CXGD
Engine
CXHA
Engine
CXHB
Engine
CZHA
Engine
DBGC
Engine
DDYA
Engine
DESA
Engine
DETA
Engine
DETB
Engine
DEUA
Engine
DEUC
Engine
DEZD
Engine
DEZE
Engine
DFBA
Engine
DFCA
Engine
DFEA
Engine
DFGC
Engine
DFSB
Engine
DFSD
Engine
DFSE
Engine
DFUA
Engine
DGTD
Engine
DGTE
Engine
DLTB
Engine
DMZA
Engine
DNAA
Engine
DNAB
Engine
DNAC
Engine
DSUD
Engine
DTNA
Engine
DTPA
Engine
DTRB
Engine
DTRC
Engine
DTRD
Engine
DTSA
Engine
DTSB
Engine
DTUA
Engine
DXRC
vinkodex.Checklist
AdBlue / SCR: NOx sensor and crystallising dosing valve
What you would check for this fault. Take it to the car.
Before you buy
Checklist
What you tick stays on this device only.
Sources
How we know
KFZ DietrichVW EA288: SCR-Kat und AdBlue-Probleme (ODIS) | KFZ DietrichTypische AdBlue-Probleme des VW EA288 Dieselmotors: Dosierventil, NOx-Speicherkat, SCR-Wirkungsgrad. ODIS-Diagnose für Golf, Passat, Tiguan.
AdBlue SpecialistSEAT & Skoda Diesel AdBlue Faults: Warning Lights & FixSEAT or Skoda diesel showing an AdBlue fault? Learn what triggers the warning, what P20EE and P207F mean on VW Group TDI engines, and how to get it fixed fast.
Precision Remaps UKVAG 1.6 TDI AdBlue & NOx Sensor Problems | SCR ExplainedAdBlue or NOx sensor faults on a VAG 1.6 TDI? Learn why SCR systems fail and when ECU solutions are required.
Information, not an expert opinion
We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.
- A fault on the list does not mean the car you are looking at has it.
- A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
- You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.