I have a mk7 fiesta and a few months ago it refused to start, when I turn key the immobiliser light just flashes I’ve tried everything I have read on the internet such as fuses and the connection from the battery, keys still open and lock the car but nothing has worked anyone have suggestions on what to try next?

2 hours ago, Dale231 said:

the immobiliser light just flashes

It should flash out a code. Google PATS flash codes. or see:

That will help to see if the problem is the key or the car.

Forscan is a low cost diy diagnostic system that can reprogramme the immobiliser (PATS) on most Fords, apart from some of the latest models. I am pretty sure it will do a Mk7 Fiesta.

12 hours ago, Dale231 said:

I have a mk7 fiesta and a few months ago it refused to start, when I turn key the immobiliser light just flashes I’ve tried everything I have read on the internet such as fuses and the connection from the battery, keys still open and lock the car but nothing has worked anyone have suggestions on what to try next?

Key may need pairing again ?

using a fault code reader on it might tell us something. It could be that the ECU is not receiving a signal from the key security chip reader next to ignition lock. The fault code should tell you if it's saying it's reading a key but thinks it's the wrong key. Also if the fault code reader will not communicate with the ECU then that would be a sign there's a problem with the ECU (less likely) or electrical connection on the way to it(more likely). car has many big multi pin electrical connectors. This fault could be one dirty pin connection somewhere.

I have never tried the PATS flashing codes that Peter mentions.This may achieve the same result as the fault code reader would.

 

Thanks for the advice all il definitely give it all a try tomorrow and find out what’s wrong 

20 hours ago, isetta said:

I have never tried the PATS flashing codes that Peter mentions.This may achieve the same result as the fault code reader would.

A decent code reader will usually give more and better information than the flash codes, but if nothing else is available, then the flash codes are a good start, and seem to be fairly universal over most Fords.

15 hours ago, Dale231 said:

il definitely give it all a try tomorrow and find out what’s wrong 

PATS (the immobiliser) is almost completely independant from the central locking, alarm and remote control system.

There is a sensor coil unit around the ignition key barrel, which is connected to the Instrument Cluster (IC). The IC then communicates with the ECU to detect a valid key, known to the car, and the ECU is then enabled. Without this process working, the ECU will not crank the engine, nor will it allow any fuel into it, nor any of the critical functions. It is just about impossible to by-pass without replacing or re-programming the ECU, so it is quite secure. But this means it is a pain when something goes wrong.

On earlier versions of PATS (say 1998 to 2004), there was an in-car PATS programming procedure to programme keys for the car (not to be confused with the central locking programming). On later versions it needs a computer diagnostic system like Forscan to be connected to the car in order to re-programme PATS to accept keys. On still later versions (like Mk3 Focus), it is still a dealer only function to re-programme PATS, a very expensive (and unacceptable in my view!) monopoly.