The XJ40 I recently bought had an ongoing problem with an ABS warning from cold. This would often cease after a few minutes. The previous owner had it repaired at a specialist and a wheel sensor was replaced.
Reading up on the system, it does a two pass test, once from cold and again in motion. The fail was from cold, therefore I couldn't see how it could be a wheel sensor.
I took the over voltage relay out and resoldered the PCB connections. Put it back in and not a problem since. Interesting that the case of the relay was marked with the previous owners name, so maybe it had been "bench tested" but not resoldered in the past!
The radio had a problem with missing segments on the LCD. I resoldered around the display connector without success, so I have noe replaced it with a DIN unit and CD changer. Details on