Hi My son car had a service at Mercedes specialist a week ago and 2 nights ago the engine light came on. He thought this morning it went into limp mode but was still able to do up to 50mph so I am not sure. Garage have run diagnostic today and said he needs 2 DPS sensors plus inlet port shutter was showing fault. £600 to do both things Was told the DPS filters were because the car only does short ish trips daily with no real chance to accelerate above 60mph every so often to clear filters?? and now too late just to blast it on motorway. No one mentions these things when you buy the car that it needs a good higher speed run every so often. co incidence or anything that could have happened at service?