2010 D5 intermittent start issue!
 

My car has developed an issue in last few days where it won't start every time. When it won't start the ignition lights up fine and everything is as normal but final turn of the key gives nothing but a single click.

I changed the battery after first failed start and was ok for a day or two.

When you try to start the car and it does start, it starts no issue. Then generally speaking you will park it up and the next attempt it wont start even after numerous attempts. Return to the car half hour or hour later and it will fire straight up. Tried the spare key as thought it may have been this but still no luck.

Last thing to add to this is we have had an error message on two occasions that said something along the lines of "Start prevented"

Any advice is greatly appreciated. Im thinking maybe removing CEM and sending to volvo diagnostics for refurb.

That sounds like a faulty immobiliser ring which is located underneath the plastic cowling where the ignition lock is. Easy to change and not too expensive. 👍

I would also check the switch feed wire on the starter solenoid whilst the ignition key is turned fully.
If power is reaching there when there's no start, there's an issue with the starter, starter wiring or starter solenoid.
If no power is reaching the solenoid, the issue is before the starter like the antenna as suggested.

Thanks for the replies! i will get that checked out today and let you know how i get on.

Ok so further to your help we diagnosed that when the fault was present no signal is being received by the starter / solenoid.

As a result i changed the antenna aerial, problem seemed to be solved and didn't have an issue for couple days then suddenly its back again.

I am 99% convinced the issue presents when the weather is warm as it generally happens on warm days in the afternoon. Any ideas around this?

With the ignition on yesterday, with non start fault present, it was stating outside temperature was 31C where it was actually low 20's.

Really not sure where i go with it from here as could take an age to finally diagnose the issue. Any help or info is massively appreciated.