I replaced the battery in my 2009 XKR

It will not start. all lights on dash come on but when pushing the start button, nothing!

What have I done wrong?

 

what does the voltage at the battery terminals read?

 

Unless you charged the new battery before installation, AND verified that the battery connections are tight and secure, the battery is still the main suspect. New batteries are very rarely fully charged when purchased - and the electronic modules in your XK require a steady diet of full voltage

 

12.6

It does everything but start

 

How hard is the brake pedal to depress? - you may have to stomp on it.

You could also try a disconnect of the battery for a few minutes to try a "hard reset" - some people like to short the battery cables together after disconnection.

 

Try this: When you get in the car, DO NOT step on the brake pedal. Press and hold the START button and keep holding it while the dashboard lights up and you then press the brake pedal as hard as you can. Hopefully, it'll start.

 

It finally started, not sure what I did but know it starts.

Thanks to all your suggestions!

 

That's the first sign ... not remembering what you forgot