Done a few of these,same fault code but on vans but same engine,first thing is to remove heater plugs and check they are working,good sign is if they are very black with carbon good chance they are faulty,earth body and put live feed to push terminal and they should glow instantly,another fault is the wiring and connections to the actual plug itself,all going well if these are ok,the heater control unit is under the fuse box on left hand inner wing on the combo vans, sorry dont know if the corsa is the same but good luck.
Neil
April 2010
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.