I recently posted about random fault codes including the DSC system failure warning light, after searching through an old thread a forum member had exactly the same faults including handbrake warning light permanently on, speedo not working, low brake fluid warning and engine management light on. His problem appeared after repairing the ABS module dry joint, so thinking there might be a fault with the module I decided to remove the main connection plug and cleaned the contacts with electrical contact cleaner.
After turning the ignition on, all the warning lights went off except the engine management light and the speedo proceeded to work. After 3 heat cycles the engine management also went off, after a week no fault lights have returned.
I should note that the soldered joint problem seems to be with 4.0 litre models, mine is a 2003 4.2 XK8 Convertible which has a different ABS module.

 

Wow. What a great (and simple) fix. I'll keep this one in reserve should I someday encounter all those hiccups simultaneously. Connectors do seem to often be the problem. My ABS/DSC fix was to improve the connects at the ABS sensors.

Congrats and Enjoy!

 

No problem, hopefully this will point someone in the right direction when these strange faults occur - particularly on the 2003 models and after. This is a great forum, it's helped me greatly when deciding which model to buy and what to look for.