Help! Immobliser/electrical problem

[mikehaslam28]

Hi everyone, I was looking for some help please. A few weeks ago my car wouldn’t start, after a short while it would eventually kick in. The time it wouldn’t start got longer and longer until it wouldn’t start at all. I had to jumpstart it to get it to the garage who did a diagnostic test and couldn’t communicate with the computer, I then sent it to another garage, this time the car seemed to have gotten worse, saying there was an immobiliser malfunction and not even allowing a jumpstart. I’ve had 3 seperate mechanics try and plug a diagnostic computer and all 3 haven’t been able to communicate with it, the last mechanic mentioned something maybe to do with the ECU or the other computer onboard (BDM I think he said?) does anyone know what it could be and what to do as im starting to give up hope of ever solving the problem if it won’t even communicate with a diagnostic, cheers for any help

 

[scotman]

What model year is your Fiesta? Is it a diesel or petrol engine? If petrol I would recommend you get the battery tested. If that passes a load test then I would be checking the ground connections. Communication failure is a problem that can be rooted in poor negative earth connections. Once you have established that ground connections are okay you can start to focus on the individual circuits. Have you recently experienced some other strange operational phenomena that might have gone away as quickly as it appeared?