My engine management light came on on my 4.2 sc range rover. I took it to the dealer they tested it and sait it was fine and put the light off 2 weeks later its back on, any ideas

The problem these days is that dealers rely on the systems to tell them what's wrong. I have a starter motor issue that the dealer says doesn't exist because the system doesn't show a fault. The fact that sometimes it just goes click and doesn't engage the starter motor is, apparently, not something they consider to be a symptom!

Until your system records an actual recordable fault I doubt the dealer will be able to do anything. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Thanks