2007 XKR Park Brake Stuck On

[andrewfl370]

My car has been laid up for the winter and first time out I find I have messages for ABS Fault and associated warnings. The car drove fine and I was going to book it in for a service, MOT and to have the fault fixed but I was off to France that week (not in the Jag).

On my return on starting the XK up I now have "Park Brake Fault" with the park brake stuck on. Now the resting voltage of the battery was 12.2v, I have since replaced that with a new Yuasa battery having read that low battery volts can cause issues and at that voltage the old battery was on it's way out anyway but the faults remain.

Is there a way to release the actuator, assuming the fault lies not in a failed actuator but elsewhere? I have read on other forums that it is possible to apply a voltage directly to the actuator and presumably this is what the Jaguar electric parking brake release tool does but I am loathe to attempt that without some definitive information.

Any help appreciated, failing that it's a call to the AA.

[mike020150]

The park brake is designed to operate within the 9V to 16V range so a dying battery could make the system lose its position information. If that has happened here, it would be worth attempting to recalibrate the park brake in case that is the fault being flagged. Recalibration should be completed by starting the car, pressing and holding the footbrake whilst raising the handbrake switch to the 'handbrake on' position. Afterwards, try a normal forward or reverse move to see if it releases automatically. Apart from using Jaguar's IDS diagnostic system (at a dealership) to release the handbrake, dealers may also have a special portable handbrake release tool (number 206-082-01) which plugs into the handbrake module (behind the centre of the back seat) and, with one push of a button, applies a voltage to the system releasing the handbrake. Access to the electric motor itself isn't easy so, if it proves necessary to apply a voltage to the motor, using the handbrake release tool would be the easiest way of doing so. Mike.

[andrewfl370]

Thanks for the input Mike. I tried to calibrate the parking brake after I fitted the new battery, no joy.

I ordered a iCarsoft 930 diagnostic tool which arrived yesterday. While I haven't had too much of a look at it I did plug it in and looked at the faults. From what I can gather it is a communication issue but need to look into that further, it seems to imply that it is not the brake actuator, fingers crossed. I have identified the wires that supply the park brake motor from the module on the wiring diagram and located them on the car... behind the SRS roll over protection on the right hand side.

The ABS problem I have is a fault with the right rear ABS wheel sensor. My plan is to replace the sensor, clear all faults, see what I get and go from there.

I used to be in the motor trade many years ago so working on cars isn't new but they had things like points and condensers and efi was fairly new and we didn't have the diagnostic tools of today.

[andrewfl370]

The AA came out today. Arrived within 30 minutes of the call, mightily impressed. He told me that the AA information was to apply 12v to a socket situated in the NSR wheel arch, failing that to cut the NS park brake cable as apparently that is the easiest to replace. Thankfully applying 12v to the motor worked and at least I have a car that I can move even if the park brake isn't working.

[mike020150]

Thanks for the update. That will be useful information to tuck away for future reference. Once the mystery's solved, please keep us updated on the comms failure issue that is causing the handbrake problem. Mike.