The last three times I drove my 2004 XJ8 in the rain, the following happened: first I get a parking brake error message and the car starts to slow down as though the parking brake is partially engaged. Then I get ABS fault. The speedometer stops working. Oh, yes, the Air Suspension fault. I pull over, shut off and restart the engine, and all is well again - for the rest of the trip regardless of any additional rain.

Any ideas as what is going on?

 

Hello! The 2004 XJ8 is a different forum...x350. But, I happen to have one of them and had similar problems with random messages that occurred only when it was raining.

For ME, it turned out to be corroded ground connections behind the passenger side headlight (RHS of car). I had to drill two holes and install two bolts to replace the factory grounding locations. Absolutely no problems since then.

--- There is an additional grounding point behind the driver side headlight as well. Mine was fine but it would probably be wise to check that one also.