What to do if you get a Top up AdBlue message on your dash? In this video I demonstrate how to check the AdBlue level on a 2020 model year Mercedes Benz. This is the A class with the two 10inch displays. This should be the same process on the other mercs like the B class, C class, E class etc.. with the ignition turned on, use the buttons on the steering wheel to navigate to the vehicle service settings and select AdBlue. It’s best to do this with the vehicle on a flat surface.
other models this may be suitable for; GLA GLS, GLE, GLC, SLC, CSL, CLA, E CLASS, G CLASS, S CLASS
The Adblue or Selective Catalyst Reduction (SCR) system is a solution for the exhaust gas aftertreatment used to reduce the NOx within the exhaust gas emissions.
For this purpose a specified amount of (Adblue) or Diesel Exhaust Fluid (DEF) is injected into the gas inlets of the Diesel Particulate Filter (DPF) and the SCR catalytic converter. The injected DEF into the exhaust system is converted to ammonia (NH3) and carbon dioxide (CO2). The resulting ammonia (NH3) is used within a special catalyst in the exhaust stream. The resulting reaction converts the unwanted NOx into harmless nitrogen (N2) and water (H2O) vapor.
The SCR system is equipped with LNT catalytic converter and DPF assembly is located in the downpipe from the turbocharger. An additional SCR catalytic converter is located in the exhaust center section.
DIESEL EXHAUST FLUID (DEF)
The DEF is a pure, odorless, colorless, synthetically manufactured, aqueous solution. The DEF is used for the aftertreatment of exhaust gases in the DPF and the SCR catalytic converter.
The SCR catalytic converter can be contaminated by low quantities of metals and thus the quality of the DEF is held to closely controlled standards. The DEF cannot be substituted or diluted with any other fluid.
The diesel exhaust fluid is not categorized as a dangerous substance, because
· The DEF is non-flammable
· The DEF is non-toxic
· There is no danger in the event of spills.
The DEF can be stored on board vehicles, despite the limitation that it crystallizes at temperatures below -11°C (12°F).
In Europe, DEF is also known as AdBlue®
WARNING MESSAGES
Filling beyond the maximum fill level can temporarily disable the ultrasonic DEF level sensor. Overfilling the DEF tank can result in a vehicle inducement condition.
It is a legal requirement for the driver to be informed of the SCR system faults. If the performance of the SCR system is reduced the dash illuminates a warning indicator and displays a warning message.
Dependent on the warning stage, the DPF warning indicator will be white, amber or red.
There are 3 possible routes to receive a fault message:
· Low DEF volume in the tank.
· Incorrect DEF quality supplied to the SCR system.
· Efficiency of the SCR system is reduced in the event of a system fault.
Low DEF Level Detected
There are 3 warning stages displayed in the message center. Each warning progresses, until a final 'No Engine Restart Possible' warning is displayed.
If the DEF fluid is not replenished within this distance, and the engine is turned off, the vehicle will fail to start. The dash displays the maximum filling level.
Stage 1 is a low priority message advising of a 'Diesel Exhaust Fluid Level Low' with the white warning indicator. Stage 1 gives 2400 km (1500 miles) ahead of any vehicle restriction in order to allow time to refill the DEF tank.
Stage 2 is an amber warning indicator with a distance reference before the DEF tank is empty and with the DEF refill volume.
Stage 3 is a red warning indicator and indicates the DEF tank is empty and restart of the vehicle is no longer possible. In this stage 3 you can fill with minimum 3.5 liters (0.92 gal)of DEF as a short term solution to restart the vehicle. The dash displays the maximum filling level.
Incorrect Diesel Exhaust Fluid Quality Detected
The system must be able to identify and respond when the fluid in the DEF tank is not to specification.
The SCR system infers the quality of the DEF through investigation of the SCR NOx reduction efficiency. The function is processed using the NOx sensors and PCM mapping strategy to continuously determine the calculated SCR conversion efficiency.
If the dash displays the 'Incorrect Diesel Exhaust Fluid Quality Detected' message, corrective action needs to be taken. The corrective action contains the draining and refilling the DEF tank with the correct DEF fluid.
The dash message center can display 4 warning stages, until corrective action is done. Each warning progresses, until a final 'Incorrect Diesel Exhaust Fluid Quality Detected. No Engine Starts Possible' warning is displayed.
#Mercedes
#adblue
#check
#2020
#Howto
#GarageTech
#Aclass
#Merc
#2019
#diy
#didyouknow
#aclass
#bclass
#cla
#refill
#topup
#slc
#howdo
#def
#scr
#automotive
#cars
#auto
#motorvehicle
#motorrepair
#diesel
#dieselengine
