2007 XJ8 , I get a constant beeping sound after the car starts moving. I have a parking brake error and following the instructions the brake will not reset. Rear pads are down to 10% and doing brakes in a couple of days. Is this all related?

Beeping is a bit vague, but it might be the parking sensors. Find the 'P' button on the roof panel by the reading lamps and press it, see if the beeping stops when the button is lit red.

As for the parking brake, what is the error, something like "Unable to set parkbrake?" What's your battery voltage with the car not running? If it's low 12s, you need a battery. Things in this car are very sensitive to undervolts of even a tenth of a volt.

Clamdigger,

I am experiencing the same parking brake beeping noise on my 2006 xj8 with the "cannot apply brake" message. I am also down to 10% of the rear pads and ordered new pads. I got a brand new battery and tried the procedure several times for resetting the brakes but it did not work and now steady beeping while driving. Let me know if the new brakes solved your problem or if there is something else that needs to be done. I hope it is not the Electronic Parking Brake Actuator as I hear they are really difficult to get to and replace. Thanks.

rjonw,
Have you corrected the beeping problem? I have been told replacing the brake pads will not cure the beeping and I can't find any info on it.

Might pay to check you haven't lost F32, the 30A fuse in rear power distribution fuse box which is the main power source for the parking brake actuator?
If the PB actuator cannot cycle through its range of motion, you will get warnings as it cannot "home" itself.
If fuse repeatedly fails, then you likely have a worn PB motor, or a cabling fault shorting something to the motor.

Worn brake pads will trigger the pad sensors which should just bring up a worded caution in the message centre display.....don't find any mention of a audible warning associated to pads.

There is another supply fuse feeding the parking brake module - Fuse F42 which is a 10A in the passenger junction fuse box.
That is less likely as it feeds a lot of other minor features as well, so losing that one would possibly have a lot of other things noticeably not working.

Mark,
Thank you for your response, yes I did check F32 and it was good. The fuse in the passenger foot well like you said operates so many things that are working it has to be good. I wish I could find where the beeper is so I could disconnect it for now. Sounds like somewhere in the drivers foot well.

Half step forward - I got the constant beeping while the car is moving to stop by disconnecting the EPB module. I know this is not a fix but it does tell me the warning beeping is do to a parking brake fault and not the brake pads. I wish it was the pads!