Thanks for all your replies, no fix yet, checked the instrument panel multiplug (ok), tried spare key no change, also scoped the signal from the transponder, seems ok, although not sure what it should look like as there is no waveform shown on autodata. Have now sent the ecu for testing and awaiting outcome. Have found an article on the pico website in their case study section, a corsa with a similar fault had a damaged can wire close to the ecu so will have alook at that as soon as I get a chance. Cheers Dave.