[SimonFD]

Hi Everyone

This is my first post on here and hopefully it will help some fellow XC90 owners who have experienced the dreaded ‘Start Prevented - Try Again’ message.

This has plagued me this summer but I made a miraculous discovery recently after several garages including a Volvo specialist couldn’t get to the bottom of it.

My Discovery - If your keys get hot the car won’t start!

My problems would always happen on hot sunny days but never when I initially left the house - only when i had been running the car for a while and had parked up.

I got stranded a couple of times on beach trips and each time the car eventually started when the temperature outside dropped. I had some long waits in car parks waiting for the RAC and then suddenly the engine would start when the shade hit my car!

This definitely seemed to be immobiliser related and was definitely linked to heat. Naturally I was assuming it was the car getting hot that was the problem and was thinking maybe failing relays or wiring issues.

During this time I replaced the antenna ring (made no difference) and even had the CEM checked and re-furbished (Again - no improvement).

My local garage couldn’t see any fault codes and a nearby Volvo specialist also drew a blank.

I was wracking my brains trying to work out what the connection to heat was when I hit on the idea of the temperature of the keys being a factor so i did a controlled experiment.

I let the keys sit in the sun for a few minutes and tried to start the car - Nothing

I brought the keys in the house and left them in my kitchen for 10 mins and tried again - car started!

I did this 10 times and every time it was the same.

Later I found that even having the keys in my pocket for 10mins with my hand on them was enough to stop the car from starting.

This happened with my main key and my spare just the same.

Lastly I tried my experiment when the car was cool but the key was warm and my suspicions were confirmed - same results.

I was so relieved when I actually made the connection as each time I went out in the car I was wondering if it would start again but now I knew I just had to keep the key from getting warm.

So clearly the problem must be with the little glass transponder chip in the top part of the XC90 Key. It makes sense as it looks like a copper wire coiled in tiny glass capsule which i’m sure must be susceptible to changes in heat especially if it’s beginning to fail anyway.

I’m getting the transponder part of the key replaced by a Volvo dealer in the next week or so for around £230 which includes the new part and coding to the car. Not cheap but better than having a car the doesn’t start!

So if your XC90 ever leaves you stranded with the ‘Start Prevented - Try Again” error message try cooling your key for a few minutes and maybe it will work for you too.

Incidentally - when I mentioned all of this to the Volvo garage they said they had never heard of it and I don’t think they were convinced about my diagnosis!