Hi
Engine management light on no effect to driving.
Took to garage said bonnet switch was not operating.
There was something on check regard egr valve said put diesel clean up in tank.
Car ran good then suddenly light comes on
Car behaves no problem.
Previous cars egr valve caused problems with engine.
If engine management uses same switch as alarm its working as alarm would not arm up when bonnet is up.
Any ideas,

 

first step is to use an OBD2 scan tool to see what fault codes are being reported then you can google them to determine next steps. Not sure what the bonnet switch would have to do with a CEL or the EGR system. Your shop would need to check fuses/relays etc to determine if there's a common electrical service path for anything not working.