I do apologize for the non much descriptive title, I'll try to work out a better title.

Yesterday my car all of a sudden stopped starting (namely I turned the key, the engine cranks that my car doesn't start). I'm not an expert but my only initial guesses were either the battery (but it's new, because I've changed recently... so no) or the spark plugs (which I've checked, they seem fine as well).

I took it to the mechanic and apparently they can't figure (at the moment) what the issue is, they mentioned that there's no power going to the engine and it has something to do with the immobilizer (but they're not sure of that either).

Apparently it's going to cost a lot of money to fix it, because and the investigation itself is going to be quite involved.

It's a second hand car, I bought it 4 years ago (a Peugeot 206). Mostly asking now if someone has some insight to share that I can use to have a discussion with my mechanic about whether or not is worth even attempting to fix it.

I might be able to give you more info if you ask.

Update There's a minor thing I've actually done now that I think about it...which is changing the case of my key fob.

Is it possible there's any relationship between this and my car not starting?

I've also found this forum where the issue seems very similar to mine.

  • 2
    For future reference, there are two ways a car won't start. "Crank no start" or "no crank." Diagnosing the two conditions is markedly different. Which condition do you have? From your post, it is really difficult to tell.
    – vini_i
    Oct 25, 2019 at 16:39
  • 1
    It cranks but it won't start. Oct 25, 2019 at 18:07
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    If the car stopped running right after you changed the key casing then it's very likely the key.
    – GdD
    Oct 26, 2019 at 14:27
  • @GdD apparently it starts now... see a comment below. Would be useful if the OP updated the question though.
    – Solar Mike
    Oct 26, 2019 at 16:10
  • I'd say that's a different problem now, I'll create a new question later. Oct 26, 2019 at 22:10

2 Answers 2


If this happened right after you re-cased your key then the most likely possibility is that you have damaged the transponders antenna on the pcb. They are very fragile. Generally the keyless entry portion is separate so it may still be working even tho the transponder is not.

I'm not all that familiar with Peugeot's since we do not have them in the states but I do know the style of key and believe its similar to the one below. If you have any local locksmith shops in your area you can take them your key and ask them to check to see if it still has a transponder signal.The antenna are easy to replace if its the problem. Its possible the eerprom on the key got corrupt as well but its rare so I would only worry about that IF they key sends signal and your car is confirmed to have immobilizer faults stored.

transponder antenna circled

  • 1
    Just back from my mechanic. Told him about the key fob, we opened the new one, moved the circuit from the old key fob to the new. We gave it a go the engine started again. Oct 26, 2019 at 7:51
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    It starts fine... But apparently there's another problem with the power supply anyway... They guess something might have gone wrong while putting pieces together. (They mentioned something with the "intake manifold") Oct 26, 2019 at 8:58
  • Thanks for the update, Yes the pcb in this key is important and holds coding data with the immobilizer system which shuts down one or more of the following: fuel, spark and/or cranking depending on the car. Hopefully they jut left a sensor unhooked now. Good luck!
    – narkeleptk
    Oct 26, 2019 at 13:36

Keys need to be paired to the car... if you lost the pairing info, by removing the key fob batteries for example then you nee to re-pair them for the keys to be recognised...

Update: this is the procedure to re-pair keys for a Jaguar X-Type (and I have one so I also have the manual...)

1 Insert key into ignition 2 Turn key to 'I" 3 Turn key "II" and back to 'I' quickly 4 times 4 Alarm system will chime once when key is back to 'I' for the fourth time 5 Remove key from ignition 6 Press any button on each key fob and alarm system will chime for each fob if it has been programmed correctly 7 Press unlock/lock/trunk etc to make sure everything works

Pay special attention to point 6, every fob you have must be programmed at the same time although you only need to use one key in ignition.

This is not a universal procedure for every car, some will need the "dealer computer" to get re-paired, others have a method that does not require a computer. Hope this is clear for those who did not follow...

  • I have the old fob, if I put the key blade + the pcb any chance it might work again? Oct 25, 2019 at 18:05
  • @user8469759 even if you put it back together as “original”, it will still need re-pairing...
    – Solar Mike
    Oct 25, 2019 at 18:33
  • What does the repairing consist of? Mostly because I need to tell something that make sense to my mechanic. I'd assume though once I mention me changing the change of key fob he might know what to do already. Oct 25, 2019 at 19:09
  • The transponders in remote keys do not loose programming simply because the battery dies or gets removed. Its stored in non-volatile memory. In fact the transponder portion will still work even with out a battery in the fob. It will get enough power to be read from the receiver around your ignition cylinder. en.wikipedia.org/wiki/Non-volatile_memory
    – narkeleptk
    Oct 26, 2019 at 0:09
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    @narkeleptk plural of issue is issues...
    – Solar Mike
    Oct 26, 2019 at 13:51

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