Sometimes your car may start to play up or you may have warning lights on your dash board that you are unsure as to why they have appeared. If this is the case you may need to take your car to a garage to be put on a diagnostic machine to read what faults are showing up on the on board computer.
Not all garages will be able to carry this out for you as they have to have the correct software for your make and model of vehicle which is why many people go to a main dealer. Although this is fine, you may find that you get charged a lot more than taking it to a local dealer that has the correct equipment. A quick call to the garage will confirm if they can carry the work out.
Once the car has gone on the diagnostic it will list a fault codes if any are found. These fault codes will then give the garage an indication as to what is the matter with the car so they can advise you.