Hello all. I've tried to research this a bit and have done several things, but cannot get this resolved ... yet. Here's the problem.

I let my 2006 XJ8 sit for about a month and the battery went dead (it was a new battery, too). After jumping the car, I got two new messages - "Cannot Apply Parkbrake" and "Step on Footbrake, press parkbrake" (or some such). After stepping on the brake and pressing the park brake, the errors cleared and things seemed fine. However, being in a hurry (and not the brightest bulb in the pack), I didn't let the car run long enough and then let the car sit for several more days. When I went to start it, it was almost dead (electronics turned on, but not enough juice to turn over). I jumped the car again and let it run. Now the car starts just fine every time. However, I am getting the two errors again. However, this time the car's park brake is fully engaged, so I cannot move the car. And nothing I do seems to release it.

I tried disconnecting the battery for 30 minutes, reconnecting, and then going through several procedures (step on brake while pressing park brake, step on brake 5 times while pressing park brake), but the car's park brake is not disengaging. When I look at everything in the trunk, all wiring looks like it's brand new.

So, any ideas what I should try next? Any additional information you need from me?

Any help would be appreciated.

 

Err.........You need to push the park brake down to release it.

You mentioned pulling twice.

 

Sorry. Mis-typed. I'll fix that.

 

Check the battery. Get it fully charged and load tested. I had a similar problem and it was a dead cell in the battery. Good luck with it

 

Silversurfer,

I most definitely sympathize. I am replacing both rear calipers with a pair I got on Ebay - in my case, and I don't necessarily think this is what you are experiencing, the parking brake mechanism, or just the caliper piston on it's own started sticking. I would park the car and the parking brake would engage as normal, This after doing a fresh pad and Rotor replacement on all 4 wheels. The right rear would not release enough (or at all) and I would get that hot brake friction material smell. Ugh, So, disassemble that one, compress the piston with my kit, sand the glaze off the pads, clean up all the burnt brake material and try again. 3 tries and I knew the caliper was not going to unstick itself. I even tried sone, err... unconventional moves like spraying a bit of penetrant/lubricant under the rubber dust seal on the piston. Tried running the piston all the way out, then winding it back. If any of these freed up the piston or parking brake, they didn't last.

Note that these rear calipers DO have issues with the pistons sticking/parking brake mechanism. I am not sure if its from people trying to force the piston straight in without rotating them, or if the tools offered to rotate and compress do not do the two actions in the right ratios, but whatever the cause they have failed me several times.

I concur with the battery suggestion. These are big, expensive batteries, that are critical in terms of electronic behavior - The X350 has a lot going on with the sheer number of compute modules, the canbus and a higher than typical reliance on correct voltage while running, while off, and while in "accessory mode" (key in position 2)

There IS a parking brake reset procedure that can be performed by a dealer or, as you experienced by either running the battery dead or disconnecting it. Unfortunately it purpose appears to be tensioning the parking brake tighter, not providing slack, again just my observation while troubleshooting my sticking caliper.

I am attaching the Chassis Workshop Manual Chassis section with sections on the parking brake - resetting it, and yes, releasing tension. Finally, if you need to reset the parking brake again, another method folks do to clear volitime memory on the various systems is disconnect the battery (both cables) and with both cables free and not touching the vehicle, touch them together for a few seconds. Re-attach and then complete the window anti-pinch/One Touch Up/down procedures.

If you are in the US, ignore the radio code bit - I have never seen it needed on US cars.


Jaguar XJ8 Battery Disconnect Instructions

1) Insure that no key is in the ignition.
2) Insure the security system is disarmed by unlocking the doors.
3) Remove luggage compartment floor panel.
4) Disconnect negative (-) lead (Ground Terminal) first.
5) Slacken the negative lead pinch bolt and disconnect the negative (-) battery lead.
6) Slacken the positive lead pinch bolt and disconnect the positive (+) battery lead.


Jaguar XJ8 Battery Reconnection Instructions

1) Insure that no key is in the ignition.
2) Do not over tighten the pinch bolts.
3) Slacken the negative lead pinch bolt and disconnect the negative (-) battery lead.
4) Clean the battery posts and coat the post with petroleum jelly.
5) Ensure the vent tube is connected and free from kink or damage.
6) Connect the positive (+) lead, tighten the pinch bolt and clip the positive terminal cover on the battery.
7) Connect the negative (-) lead and tighten the pinch bolt.

After Reconnecting the Battery

1) After the battery has been reconnected and the ignition switch is turned to position II, the message center display, will initially show an erroneous reading i.e. - - - - - - . This will remain until the bulb check sequence has completed, when the correct recorded mileage will be displayed. This is a normal function of the instrument cluster.

2) Reset the electric parkbrake.
a. The message APPLY PARKBRAKE will be displayed when the ignition is switched on.
b. Depress the footbrake and pull the parkbrake switch up to apply the parkbrake. This is required to reset the parkbrake system which will now function properly.

3) Reset the electrically operated windows anti-trap function.
a. Fully close the window, hold the switch in the close position for 2 seconds and then release the switch. Wait for 2 seconds, do not open the window.
b. Again, select the same window to close, holding the switch for a further 2 seconds.
c. Check to confirm the operation by opening the window and then use the one-touch operation to close the window.
d. Repeat steps a through c for the remaining electrically operated windows.

4) The radio will not operate until the correct security code has been re-entered.
a. Code will appear on the display. Enter the code (4123). When entering the code, if a “beep sound” occurs begin the code entry over, starting with the first digit. This “beep” was provided to indicate the starting point for the code entry.
b. If the code is not properly entered in 3 successive attempts the radio will not accept any entry until the radio has been left on for 1 hour. After 1 hour in the “on” position the radio will accept 3 additional entries.

5) Reset the analog clock on the dashboard to the correct time.

 

Blairware - Thank you for the detailed instructions. I did as you've detailed and my park brake is still engaged. Besides the error telling me to apply the footbrake and the parkbrake, I also get an error saying, "Cannot Apply Parkbrake". So, it appears the button is incapable of working at the moment. I need to pull the battery and have that checked to see if there is an issue there, though. I will try to do that this evening with the misses is back with the other car.

Thanks for trying to help, though. I do appreciate it.

 

Try this ....it is the release park brake to service position sequence....with the engine running and parkbrake applied, push the release lever down with one hand and while holding it down, turn car off and remove key

 

Thanks ... however, that didn't do the trick. I still get the "Cannot Apply Parkbrake" error and the parkbrake is still engaged, preventing me from moving the vehicle.

 

well then...I would make absolutely sure that the battery is fully charged and holding a charge....if the battery is good then you have 2 choices...tow to dealer or jag shop....or cut the cables from underneath that apply the park brake

 

Heading to the autoparts store with the battery to have it checked tonight. It's still under warranty (less than 6 months old). I'll let all of you know what happens.

Obviously I can't cut the cables (nor would I). I wouldn't be able to get the car to pass inspection with out a working emergency brake.

 

Alright. I had the battery checked. It appears fine and now is fully charged. Once placed back in the car, I STILL get the "Cannot Apply Parkbrake" error. As a result, I am still not able to get the park break to release. Ugh.

 

Assuming that's a regular stock battery which is in the car, I can't imagine that a relatively new battery would discharge to that extreme after a month of sitting idle, and in just a few days no less. In fact, I would suggest placing a DC amp meter on that battery while the car is at idle. I wouldn't expect the current drain to exceed much over 20mA tops.

 

I currently don't have one (a DC amp meter), so I'll have to pick one up. Thanks.

So, where exactly is the unit for the electronic parking brake? How do you access it? What else can be checked besides the fuse (it is fine), the battery (it is fine), and doing all the various "step on brake and apply park brake" things to attempt to disengage/re-calibrate the park brake? Is there a manual way to disengage the park brake (apart from cutting the cables!) or re-setting it?

 

Okay! Not sure what Jaguar magic just happened, but my emergency brake is now working normally. Thankfully. I decided, one more time ... I mean, for the third time today ... to disconnect the battery, wait, touch ends, reconnect, and try again. This time, for whatever reason, the "Cannot Apply Parkbrake" error did not show up. Only the standard "Apply Footbrake and Parkbrake", which I did. And then ... MAGIC! The red brake light re-appeared on my dash and when I put it in drive, it went away and the car was released! I turned off the engine and restarted it just to check again and all is working normally. I'm not sure what was different this time, but I am just glad it worked.

So, here's a question - does it matter, when connecting the car battery, if you connect the positive before the negative? Is there anything adverse that could happen if you do it the opposite way?

 

I think the answer to both questions is; I doubt it especially since there is no mention in the OM battery connection and charging section.

The electronic copy of the OM is available on this forum if you want it.

 

Glad to hear that the gremlin has left the vehicle. I always connect negative last, and remove negative first, as well as TRYING not to cause too much arcing between the post and the terminal. Simply because cars are negative ground and sensitive electronics (read Jaguar electronics) generally dont like multiple power cycles within a split second.

Jaguars instructions state the same order. Curious if you did negative last on reconnect.

But a modern vehicle should be able to manage most events, and these cars are generally reliable, as long as the battery is sound.

I hope you never see a return of this one, but in the interest of keeping it operable, you may want to have someone run the parking brake calibration routine. If it were me, I might further try to see if I could lubricate the cables and make sure both are up and on top of the sway bar links. Ive only owned 2 X350s but BOTH had one side where someone did a brake job and let the cable be stretched AROUND the link. Bloody amateurs!

Happy motoring.

 

It matters only from a safety point of view (the electrics couldn't care less), in that if you imagine this operation being done countless times on countless cars then sooner or later a tool will bridge the battery terminal being connected and some metal other than the battery (which is generally the car body or connected to it).

Whatever the polarity of the car body (i.e. whichever terminal connects to it), connect it last. That way no nasty current/etc can occur whether you short the first or second terminal to the body.

For most cars nowadays, which have the -ve connected to the body, connect the -ve last.

The same reasoning means disconnect the body terminal first.

 

Well, we're at it again. Sigh. I started the car today to find a new error - Parkbrake Fault. Once again, the park brake was engaged, so I could not move the car. I was getting no other error messages. So, I turned off the car, disconnected the battery, let that sit for about 30 minutes (mainly because I went inside to get dinner started), touched the two ends of the battery cables together, put the cables back on the battery, and started the car. Now, we are back to square one - "Apply Footbrake and Parkbrake" and "Cannot Apply Parkbrake" (once I try to apply the park brake, per the first error message).

I've noticed one thing, though this probably has nothing to do with this. Each time that I reconnected the battery, the horn started honking and I had to click the keyfob to stop that. However, the one time the park brake worked properly, this did not happen. When I re-connected the battery cables, the horn did not start to honk.

 

BTW - Where exactly is the electronic Park Brake Module located?

EDIT - Never mind! I was able to find it (in the trunk/boot on the right under the carpet).