Peugeot 5008 engine won't start immobilizer error

Sounds like an immobilizer fault. I had a similar problem with my old Opel Astra a while back. It would crank but never fully fire up, or start and immediately die. Did you try your spare key? Does that make a difference?

Thanks for the reply! Yeah, I tried the spare key, but it's doing exactly the same thing. So, if it was the immobilizer on your Astra, what did you end up doing to fix it?

Okay, since both keys are showing the same issue, it's less likely to be just a key fault. In my case, it turned out to be an issue with the immobilizer module itself needing a reset. Although a bypass might sound appealing, I strongly recommend getting it checked out by a workshop with the proper diagnostic tools. They will be able to pinpoint the exact cause and reprogram or replace the necessary components. Messing with the anti-theft system yourself can cause major headaches.

Thanks so much for the help! I took it to a local workshop and they diagnosed it as incorrect key programming. They recoded the key and it's working perfectly now. Cost me 45€, what a relief!