I bought this car in march 2007 and at the time was not knowledgable enough to realise there was a more serious fault than was notified to me by the vendor.Whilst road testing the car he informed that the a.b.s. warning came on occasionally and that if i turned the ign off this would clear. The car had also been fitted with a new a.b.s. ecu 4mths previously.The problem was ok for about 6mths, then it got worse.As well as the a.b.s. warning staying on longer the airbag warning and anti-pollution warning came on.After a while the a.b.s. & airbag warnings went out but the anti-pollution stayed on. Iv'e had the car in 1 garage and he whipped the diag pc on it and cleared the faults that were present.The car was fine for about 2 weeks then the faults started appearing again.Took it back & the previous faults had not been recorded despite being on for more than 30secs, the required time for the faults to be recorded.Instead the following fault codes were present:- PO500-car communication vehicle speed invalid. UO121-car communication.No communication with the esp ecu.PI351-preheating relay circuit stuck in open position.PO483-cooling intergrated into ecu open circuit or temp too high.Then took it to another garage, again no faults had been recorded, rec I take it to peugeot which I did only to be told it needed a new a.b.s. ecu which I obviously didn't believe as the faults were still there soon after a new ecu had been fitted.Started asking around and I seem to be getting the message that it is a faulty wheel sensor or a fault in one of these circuits.Any pointers woul be greatly appreciated and suggestions on how to check wheel sensors and circuits.I do know it has something to do with checking the resistance but exactly how I am not sure.Got the tackle to do it but need the knowledge.