I have a red engine light on with the words check

So the garage couldn't get a fault code from the car? Did you take it to a main dealer?

i have a warning light on its a red engine with the words check had back to the garage they changed the fuel filter and sensor but the lights still on their computer cant get any reading from the car and the engine managements on so the car is running very flat any ideas please the main dealer is too far away .it started with a cloged fuel filter had it replaced but light stayed on it lacks power till you hit 2000 rpm any ideas thanks