I have just changed my front shocks to Bilsteins and on the drive home the ABS buzzer went off and the ABS light came on. Also the speedo is not working.

Any suggestions (I will start with the ABS connections on the front) on what it may be?

 

Sounds like you are on the right track, start with checking both front wheel sensors and associated plugs and wiring.

 

The speedometer is run from an output of the ABS unit. I would check to see that you have power to the ABS computer and check the connections to the front sensors. A Hammer or PST2 will tell you exactly what is wrong.

 

I had exactly the same problem a couple of months back,you may also find your rear spoiler dont automaticaly raise,I had that also.
It turned out to be loose conections in the main ABS controler socket,but it took me a couple of frustrating weeks to suss it out,after going through all of the checks on the speed sensors,brake fluid levels,relays,fuses etc,etc.
The conections in the ABS main socket looked ok on first inspection,so I discounted it,then as I was checking the circuits from the socket to the speed sensors with a circuit tester,(no relevant readings found)I plugged the socket back in to the ABS unit and hey presto,no buzzer,warning lights,and evrything worked fine,and has done since.
The only conclusion I could come to was ,when I was probing around inside the socket with my circuit tester,I guess I must have tightened the terminals.
Hope yours turns out to be as simple,
Best of luck Marc.

 

Did you check the fuse? Both the light and no speedometer occur if the fuse is blown.

 

wheel speed sensor?

 

Yes it was a wheel speed sensor (ABS) - the plug was pushed into the socket properly.

Thanks for all the help Ken