SKOD SUPERB 1.8TSI PETROL NON START

I wonder if anyone out there has had this problem we have a skoda superb 2011 4x4 1.8 tsi petrol manual, that won't start the battery is fine and when you try to start it the dash says check deadlock see manual, nothing in the manual plug code reader in no faults present old or new Skoda dealer has had it for six weeks can't find anything wrong with it, at first it was intermittent start i think the problem didn't occur with them, got the car back started ok first few days now it won't start at all.