Went to start today and nothing happens. Battery good, doors etc open, everything works but when turn the key nothing, tired another battery just in case (as spoiler has deployed). All the dash lights come on but no difference apart from it did make 1 effort to crack over but that was only for about 2seconds.
Any suggestions on what to check next?

 

Discconect the battery for a few minutes, clean both terminals and the ground at the fender from the negative cable. After reconnected try to start; If you get two attempts ( car usually starts for 2 seconds then stops) after that you can not even get the starter to engage you have a problem with the SKREEM module. Use the search box for SKREEM, all kinds of info, but in a nut shell you will need to purchase a replacement from needswings.com about $700. There are a couple other sites that can attempt a repair of the module. You can find them in the threads on the SKREEM problems.

The other possablity is a problem with the RCM Relay Control Module. But it will give a little different start problem than what you have described. Please follow the info in the first paragraph then let us know exactly what happened.

 

Thanks for the advice.....was a simple fix after all that.....the keys needed to be re-synchronised.....saved a major expense thankfully.

 

Synchronizing the keys only means you can open the doors remotely it does not help in starting the car. The fob has two separate functions, one is to open the door and the other to start the car. The first consists of a transmitter and the second a transponder chip.
I fear you still have your initial problem if in fact there was one.

 

The doors would already open with the fob, all the lights on the dash came on but the engine just wouldn’t start. I followed the instructions from the dealer to try synchronise the keys....and now the car starts perfectly on both keys.
Only time will tell if it was that simple or there are other underlying issues yet to surface.

 

I know the doors opened, you said so in post #1, I was answering your second post.

 

I have the same problem with 2005 w/only 28000 mi. I thought it only needed a new battery, Dealer said battery & alternator were good after charge, then starts right up & runs great, next day won't start again do I have same prob. or something diff.