I have a 1.8 tddi 1999 which i bought with a faulty pump, i replaced the faulty PCM(Pump Control Module) on the top of the pump with another one and car was perfect for 6 weeks then it blew the PCM again, i sent the PCM off to be repaired and received it back and it worked fine again for two weeks and then the car blew it again , this time the module was not repairable. So now i have another PCM but i don't want to replace it, well not until i find what is making the car blow them, mainly because its the only one i have left.

So has anyone encountered this problem before or know where the likely candidate is, that is causing this?

Just to clear terms up, the PCM is what many refer to as the pump ECU
Just to add that no fuses or relays were affected when this happens its just the control module itself that's blowing