Parking brake locked on.

[anaw]

OBD message says park brake motor in open circuit. I inadvertently allowed the battery to run down and the car failed to start. Since then I have charged the battery and driven the car although warning messages 'air suspension fault' and 'cannot apply park brake' have shown. I have gone through the hard dump procedure but the EPB fault still shows and the the brake is locked on. It did this yesterday ( at the fuel pump!) but it released and I drove on.
I know that other car makes have the same problem but my lifelong love of Jaguar is waining. Any help will be gratefully received.
With thanks - Tony. (2007 XJ Sovereign and 2006 XK convertible )

[anaw]

Further to my query above I have now freed the EPB using the useful info in Quikcat's post on Jaguar Forums.com. HOWEVER, the EPB is not working ( although the motor is), there is no response from operating the switch. The fault outlined above still shows on the Autel and I also have SCP (JI 850) Coms Bus Fault and not a clue what that means ! The car drives fine but the cabin ambience is somewhat spoiled by flashing lights, gongs and fault messages.
Any help gratefully received.
With thanks - Tony.

[J44EAG]

Dis-connect the battery for about half an hour, reconnect and see what happens.

My car gets little use and the battery is often in a depressed sate during winter months. It plays havoc with electronic reliability. It is unlikely that the switch has broken. The motor could conceivably become jammed at one end of its travel. The park brake calipers may have had little or no attention for years and pads and pistons somewhat seized. The pistons are wind back with a suitable brake wind back tool kit. Plenty on ebay. I have done a magazine article on this job and again there is detail in our brake section in this 350 part of the site.

I ripped my car apart when I acquired it at 79K miles covered three years ago. Most of the issues were outside the normal servicing schedules. I suppose it took me eighteen months to get the car to the state I needed. That is old cars for you and probably the reason any person with enough funds, buys a new car and chops it in for another one every three years. Most modern Jags will need a fair bit of invasive surgery every five years or so. It is the name of the game and you just have to work through the list of maladies one by one. I don`t suppose any other make is any different.

Mike

[anaw]

Thanks Mike, I had followed the instructions in your previous posts but to no avail. The motor operated when I bridged the terminals in the plug so the car is now mobile but no EPB just lights and gongs. I think I'll need to try a replacement module. Your thoughts?

On the matter of 'old cars', at 73 yoa and with limited resources I have always driven 'old cars'. Even my XK purchased with 5,603 miles on the clock was nine years old, it too had lots of electronic issues all down to a low battery voltage, my previous 1996 XK8 had no problems in seven years. My real old cars MGBs, Scimitar, Rover V8s, Lotus and Triumph PIs had issues but all easily addressed. I don't recall my fathers SS 3.5 saloon ever having a day off work.

Grateful as always - Tony.

[J44EAG]

Replacing parts without proper reason on an off chance you will get a positive result is a risky and expensive game with no guaranteed outcome.

An informed diagnosis forms the first part of any repair work. Having done the diagnosis, it is important to understand the problem. Once an understanding has been reached, a logical and rational fix can be tried. Replacing modules in the hope of success falls into the shot in the dark category. I`d not be replacing a module until I was certain that the park brake calipers and pads were free working and that the pads still had some lining material left on them. It is also advisable to start from the basics and work forward rather than the other way around.

Just my take on the matter.

Mike

[anaw]

Thanks Mike, I have a vehicle lift and had checked the operation of the brakes. The pads and discs are almost new and all seemed well.
I have put the car into the garage for a more sophisticated diagnostic reading so here's hoping.
Many thanks for taking the time. - Tony.

[PaulGover]

The other common problem with the EPB is hidden shorts in the harness connecting to the motor. It can either suffer from the insulation abrading on the suspension members it route through, or corrosion internally. Mine died that way, and my local Jaguar dealer sorted it out for a reasonable sum (compared to a new motor or harness, say). (I too have hidden shorts - my wife says they make my knees look silly)

[anaw]

Thank you Paul for bringing a smile to what has been a troubled face. Thanks to all for your time and suggestions, the problem was a faulty battery less than two years old !
Cabin ambience is now as it should be and my love of Jaguars is returning.

Merry Christmas.

[J44EAG]

I`e been working this site for many years now and every year without exception, as soon as the cold weather strikes, a rake of Jaguars begin showing strange electrical/electronic gremlins and we seen an increase in people on this site asking for advice on their car issues. Its never been any different!

Many of these issues stem from poor battery condition which is usually caused by old age ( four to five year old or more) which greatly affects terminal voltage and storage capacity. Batteries can die of lack of voltage or lack of storage....or as is usually the case, a combination of both. A battery never lives for ever and really should be regarded as being a consumable part which might need replacing every four years to maintain reliability. I`m usually lucky to get four years life before it goes flat on its back. Erratic or slow starting usually gives the game away. Batteries can be ok in the summer but come the winter, the fan is going full blast, heated screens and seats are in use and the battery collapses under the load. There`s a suprise!

With many modern Jaguar models, after a cold start with a decaying battery, it is quite usual to see the ABS legend show up and the electronic handbrake to come out in sympathy. Restricted performance can also occur. Add to that dropping glove boxes, opening fuel caps, valet mode and the console light staying on are further well know pointers towards a low battery condition. In fact its not those systems at fault. It is usually a failure of the onboard diagnostics to complete as they should do on each engine start due to the battery being in a perilous state.

It is quite amazing what a transformation can occur when a new battery is fitted. All the troubles disappear. Note that these cars need decent premium grade batteries. Forget the cheapo basic technology Halfords jobs. Go for Jaguar OE, Varta or Bosch premium silver types. You won`t regret spending a bit extra. It makes a big difference to electrical platform stability.

Mike

[iRS]

Coincidentally my car has just developed a EPB problem. Luckily it seems to have failed with it being off, so I can drive the car, but like Tony says the warning gong drives you crazy. Does anyone know how to turn this off?

The battery is only 2 years old and a Bosch and although the problem occurred yesterday at sub-zero temperatures, its still there today. I had a hint of something not right a couple of months ago, so perhaps that was a warning of the motor about to fail, or as Paul says, it could be the wiring. I'm hoping I do not need to get up inside the rear suspension frame to fix the problem. I see there's a lot of information on Jaguar forums so I'll see if I can connect direct to the motor and see what happens.

[iRS]

Posting a circuit diagram I found on one of the other forums.

I've just been looking at this in detail. These details - and the electrical diagram - seem to relate to cars from G45704. ie later cars from sometime around mid to late 2005.

I'm just adding the instruction from the other forum:

a) disconnected the car battery and removed fuse 32 from the fuse box next to the battery
b) took out the right hand carpeting in the boot (trunk for any US people) and took the connector off the bottom of the black plastic EPB module (it has 4 thick wires and with brown +ve and black -ve although power supplied through fuse 32)
c) placed a 30 amp blade fuse in the slot with the red/white cable wedged with a small crimped copper wire (otherwise it is a loose fit). Spare fuses are in the compartment on the panel at the rear of the boot to the left of centre
d) connected a cable with a normal spade crimp connector to the green/white
e) I used a battery booster to provide 12V and connected -ve to the other side of the 30A fuse and the +ve to the green/white connected cable for a second or two.

You should hear the electric motor run and hopefully the lovely sound of your brakes disengaging!

Just for clarity, these are not my instructions, they are someone else's from one of the other forums.