Code readers are available from around £20 or so. eBay has dozens. OBD2 reader is what to look for. Alternately there is a free programme - Freessm - downloadable to laptop, which gets connected to the car's OBD port via a cable, the type of which escapes me. Alternatively, your car should have an obd read option which displays the various fault codes on the dashboard. You get to this via a series of switches (headlights, trip meter) the sequence of which currently escape me. If I find it I'll send it. There are also small plug in readers which BT connect to a downloaded app on your phone. Lastly, most half-decent garage should have a code reader so you might want to ask if you have a friendly local guy.