AdBlue fault: “no start in X miles”, causes and affected cars

Recent diesels inject AdBlue (a urea solution) into an SCR catalyst to cut nitrogen oxides. The system became the "fashionable" fault of the late 2010s (Fiches-auto): breakdown services report a sharp rise in AdBlue call-outs (Caradisiac). The typical symptom is an "emissions fault" or "no start in XXX km" message (Caradisiac).

Why the "no start" message?

As the message says, the countdown ends with the car unable to start: it leaves time to get to a garage, provided you do not ignore it (Caradisiac).

The most common causes

• The tank and its pump: on Peugeot, Citroën and DS models, the tank is combined with the AdBlue pump, which makes the bill heavier; Fiches-auto blames the supplier shared by Stellantis and Toyota (Fiches-auto). Test-Achats mentions repairs of up to €3,000 (Test-Achats).
• The AdBlue injector, which can clog or leak.
• The NOx sensors, which check the emissions system is working: a faulty sensor triggers the same messages (CarVerif, Audi Q5 II).

A garage must read the fault codes to tell these causes apart before replacing anything.

Stellantis compensation

French consumer group UFC-Que Choisir referred the matter to the competition and consumer authority (DGCCRF) after more than 1,700 reports (Caradisiac). Stellantis opened a compensation platform for affected Peugeot and Citroën owners, but Test-Achats reports many refusals without explanation (Test-Achats). Keep every invoice and exchange with the garage.

Before buying a used diesel

An AdBlue warning, a start countdown, emissions fault codes or an engine warning light are reasons to walk away (CarVerif, Citroën C3 Aircross; CarVerif, Citroën C5 Aircross). Ask whether the AdBlue tank has already been replaced and, on a Peugeot, Citroën or DS, whether compensation was obtained.