MAN · Truck & Bus · AdBlue Fault Solution

MAN Truck AdBlue Fault Solution

We solve AdBlue (SCR) system faults on MAN trucks and tractor units with ECU software: NOx sensor errors, pump and heater faults, quality warnings and power derate. The cause of the fault is diagnosed first and the original software is backed up.

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On trucks and tractor units an AdBlue fault starts with a countdown on the dash; when it expires the vehicle is limited in speed or torque and a loaded truck is stranded. The most common causes are the NOx sensor, the pump module and a crystallised dosing injector.

The SCR system injects AdBlue (urea solution) into the exhaust to reduce nitrogen oxides. It consists of a tank, pump module, heater, dosing injector, NOx sensors and a control unit. When one of these parts fails the ECU first warns, then starts a countdown and, when it expires, limits power or speed.

The most common faults are the NOx sensor, a dosing injector and lines blocked by crystallisation, and heater and pump modules that fail in the cold. Poor-quality or diluted AdBlue also shows up as a quality fault. We identify which part is actually at fault by diagnosis and recommend the solution accordingly.

When is it needed?

AdBlue warning and countdown
Pump / injector / NOx sensor failure
No-start lockout caused by a system fault
High repair cost

Typical duration: 2–3 hours

MAN AdBlue Fault Solution: supported control units

Control units for which our library holds a verified solution for this service on MAN: BOSCH EDC7C32, BOSCH EDC17CV42, BOSCH EDC16 and BOSCH MD1CE100. The same model can carry a different ECU depending on build year and engine option; we confirm compatibility from a photo of the ECU label or from the file read out.

BOSCH EDC7C32 BOSCH EDC17CV42 BOSCH EDC16 BOSCH MD1CE100

MAN models

MAN TGX MAN TGS MAN TGM MAN TGL

AdBlue Fault Solution for other makes

Iveco DAF Volvo Isuzu Renault Ford Trucks Mercedes-Benz Scania Mitsubishi Fuso Karsan Sinotruk Beiben

Frequently asked questions

What are the symptoms of a MAN truck AdBlue fault?

An AdBlue or emission warning on the dash, a remaining distance or time countdown, NOx sensor fault codes, power or speed limitation and, on some vehicles, a start inhibit are the most common symptoms.

Can a NOx sensor fault be solved with software?

It depends on the ECU type. The condition of the sensor, the wiring and the SCR catalyst is diagnosed first; if replacing a part is the better and cheaper route we say so plainly. A software solution is applied when our library holds a verified solution for that ECU.

How long does the job take?

Most ECUs are read and written through the diagnostic socket and the job is completed the same day. Some units are removed and worked on the bench.

Can the original software be restored?

Yes. The original ECU software is backed up and archived before the job; the factory setting can be restored on request.

Why does the vehicle cut power and limit speed when there is an AdBlue fault?

When the emission system detects a fault, the ECU first gives a warning; if the fault is not fixed it reduces torque, and at the next stage it limits the vehicle speed. This is how the system is designed to behave. Power returns once the cause is fixed or a software solution matching the ECU type is applied.

Will a reset clear the AdBlue warning?

After the tank is refilled, the warning goes out by itself on most vehicles. If it stays on after topping up, the cause is usually the NOx sensor, pump module, heater or level sensor; a reset alone does not last, and the warning and power reduction return. The fault memory is read first and the source identified.

The vehicle cut power on the road. Can it be dealt with where it stands?

Most engine ECUs are read and written through the diagnostic socket, so the job can be done where the vehicle stands; some units are removed and worked on the bench. Send us the location and the make, model and model year of the vehicle on WhatsApp.