my son called to say his 1.3 diesel combi van started ran for 2,3, seconds then cut out,it would not start again,after plugging in my mates fault finding computer,it gave the code PS400 which relates to the EGR valve all the things suggested on line to check the valve involve the engine running to do them,his won't start so i am unable to perform the suggestions any help or guidance would be much appreciated thanks,Shaun