The light comes on, then the counter runs down: in kilometres or in remaining starts. At zero, the engine is limited or no longer restarts. An AdBlue light is not a sensor to replace, it is an investigation: we measure first, we replace afterwards, and only what is at fault.
When the AdBlue system detects a fault, it lights a warning and then displays a countdown, in kilometres or in number of starts depending on the manufacturer.
At zero, the engine goes into reduced power and speed, or refuses to restart after being switched off. This is not an additional fault: it is the anti-pollution regulation being applied.
Clearing the fault does not reset the countdown. Only repairing the cause gives the vehicle back its normal operation.
Housed in the pump or the module, it is the part we replace most often. It gets forgotten during servicing.
Upstream or downstream, often at fault and just as often wrongly blamed: it is checked and cleaned before being condemned.
Fouled or crystallised, it no longer doses correctly. Its actual flow is tested before any decision.
Too old, diluted, contaminated or stored in the sun: the quality sensor detects it and triggers the fault.
White deposits in the pipes, the injector or the mixer, especially on vehicles that run little or in town.
The expected pressure is not reached, and the whole dosing suffers.
In the tank: a fault that appears in winter, or a level misread by the control unit.
Wiring harness, oxidised connector, power supply; more rarely the control unit itself.
Last, and only when everything else has been proven good.
LNVI is the first truck workshop driven by artificial intelligence : every diagnosis is cross-checked against the vehicle's complete history before a single part is ordered.
If the particulate filter or the EGR valve are also at fault, see our page DPF and EGR cleaning.
Only until the counter reaches zero, no more. The countdown does not go back up until the cause is repaired: come to the workshop at the very first warning light, before the engine refuses to start again.
Only if the tank was really empty and the fluid added is good. Otherwise, the fault lies elsewhere: filter, injector, sensor or pump.
You can reach the workshop at reduced speed. Do not set off on a round: at the next stop, the engine may not restart.
The quality sensor flags it with a fault. At the workshop, we test the fluid taken from the tank. Doubtful AdBlue means draining and cleaning the system.
Not straight away. It is often wrongly blamed: we first check the filter, the injector flow, the fluid and the exhaust tightness.
Yes, at around −11 °C. The system has heaters: if they fail, the fault appears mostly in winter, on a cold start.
Yes, like the other filters. It is the part we replace most often on this system, precisely because it gets forgotten at services.
Because the part replaced was not the cause. We start again from the measurement, and the repair is only validated after a road test with no return of the fault.
Call the workshop or book an appointment at the first warning light, before the vehicle is immobilised.
We have been working with this garage for years, and there has never been the slightest problem. Very professional team, top notch!
Hugues K.A team at your service. Quality work in record time. Deadlines are always perfectly met.
Pascal M.Exactly the kind of partner we needed. The service is very fast and lives up to our requirements.
Valérie G.