My car wont start as the red security light keeps flashing repeatedly although some times it does start.any ideas please as to how the immobilizer works ie what does it cut out,as i can here the fuel pump run, is it in the ecu?

 

Probably the key isn't being recognised.

possibly needs a pats ring which clips to the ignition barrell.

 

Is that a simple fix? i drove it to the ford main dealer and it drives 100% and the guy there said i reckon it will be your petrol fuel injection pump and that will be Ł1750 plus fitting as its to do with the immobilizer, i said well its a right off then and drove home no problems, next day no start again!

 

The Immobilizer is called Pats. Passive anti theft system. If it’s a petrol it’s in the ecu and can not be bypassed. With you saying about the fuel pump I am guessing yours is diesel ?

first thing to do is pull the codes with a reader.