- MAC OSX
- Member Since: 08 Dec 2016
- Location: Newry
- Posts: 52
Adblue System Check
If the DEF (adblue) system fails its switch on check does the vehicle refuse to start or go into a limp home mode?
- DieselRanger
- Member Since: 12 Oct 2017
- Location: God's Country, Colorado
- Posts: 770
In North America at least, you're supposed to have ten starts once the AdBlue is empty and/or there's a system failure. Reasoning is that here, you can be pretty far from civilization at times, even on an interstate. Limp mode shouldn't be activated unless NOx or O2 sensors fail, or things like the fuel pumps, EGR, turbo, etc fail.
If you're considering a bypass, that will probably require some sort of ECU flash to trick the sensors into providing the correct signals (tank, quality sensor, injector, SCR sensors, NOx sensor, etc), and this is fraught with risk as the vehicle's sensors often provide their information to multiple systems. If you leave the DEF tank full, it must be filled to the brim of the fill pipe to avoid crystallization but you'll still end up with clogged feed line and injector, requiring replacement unless you drain and flush those completely and disconnect them from the tank. Or you can fill the tank with water, but again, unless you code around the sensors then you'll get a DEF quality error and "no restart in XXX miles" warning.
These systems are designed specifically to be difficult to bypass.
