If the Adblue system is not switched off its costing you extra money everyday. When the system fails the truck or earth moving machinery will go into limp mode which has to be fixed, which costs more money and downtime. The most common fault with the SCR system is the NOX sensor costing approx £900, next is the Adblue ECU at a cost of £5000. We have had customers who have replaced the NOX sensor every 3 – 4 months until they fitted our box and now they have no problems.