is emmissions add blue. mine did it once
hand book will tell you if it comes on to clean your dpf
Park the vehicle in the open air at least 2 meters clear of passing pedestrians, buildings or combustible materials. • Engine at idle • Coolant temperature at least 60°C • Park brake applied • Foot brake not applied .
press the button on dash.
engine will then rev up and down like mad book says it takes about an hour.
1st time it came on I did this. waited and waited well over an hour nothing happened was still revving it balls off.
so I gave up turned the engine off. started up again to drive back to the yard light still on after about an hour driving I looked down noticed it had gone off never been back on again.
was told it usually comes on if you do a lot of stop start multidrop deliveries. it just needs a good blast up a motorway to enable all the rubbish to be cleared out of the system