My 1996 2.5 diesel transit won’t start after removing the battery 6 months ago and putting the van in storage, I have checked all the obvious things battery fuses etc, but the problem persists, I suspect it is something to do with the ford pats immobilizer as I get nothing other than a click from the ignition relay when I turn the key, and the warning light comes on the dashboard, there are no other noises, and I can’t hear the fuel pump whirring like it usually does, is it possible for the immobilizer to lose the code from its memory due to the battery being removed for a long time I have tried starting it with the red master key but it’s still the same.

I had a mechanic look at it briefly and he suspected the immobilizer is not recognizing the key, I cannot check what the immobilizer sentry light is doing as this would have been located in the original roof and the van was converted to a catering van in 2001 so the red led light was either removed or covered over when the new body was fitted.

If there is a fault with the pats transceiver key reader can this be replaced or would it need re coding or something

Any ideas would be helpful