Hello, Today I picked my son up after work after driving 20 minutes to the in laws house. Got back in my car and started it, parking brake fault light on, car wont move and the brakes wont release. Checked 30a fuse in trunk, ok. I tried disconnecting the 2 plugs in the module by the battery, didn't work. looking for some ideas, I would like to be able to just move it out of their driveway and get it up on a jack in my garage where its a little warmer, or take it to a shop if I have to.
My battery is about a year old, just replaced it when i had some transmission issues.
I can't hear the motor on the parking brake trying to work like it usually does when you pull out the key, but then again its already engaged.
I also tried moving the car back and forth a little but she just beeped at me and wouldn't loosen up.
looking for some tips to disengage the park brake and troubleshoot the issue.

 

One quick thought:

I wonder if the charging system was on the fritz and the battery was slowly running down. That little battery indicator on the dash is only good at warning about some electrical faults, but not all.

From forum experience, a parking brake problem immediately after engine start is a "canary in the coal mine" for low battery voltage. It's often the first fault to appear when the battery runs down. It's easy enough to rule out. Check the battery voltage before engine start. It should be 12.6V or above, a VERY high standard.

If indeed low, hook up a charger overnight and then retest in the morning. You may be pleasantly surprised. Fingers crossed...

 

I will definitely check that tomorrow, I didn't have my multimeter with me at the time and would have checked that, I have read about the low battery issue with the parking brake cruising though the forums.
Thanks for the Input! I appreciate it.

 

Charged Battery overnight, even took it out and had it load tested, all good...Battery is charging at 15 volts for a few minutes then drops down to 13.2 to 13.3 volts while running in the car under full load with radio, lights fan etc.
I had to Force the motor to release by hooking up some wires (ground and 12v) from the left harness that plugs into the control module (green and red fat wire). So I know the motor works. I got the car home, Yay.
Problem now is it thinks the parking brake is on and beeps constantly while i drove it home, the manual switch for the parking brake does not work either...the brake will not re-engage when taking the key out also.
anyone have any ideas with the extra info I have found?

Could the ignition switch have anything to do with this is does feel a little different when pulling the key out like a little more loose and i know the parking brake goes on when you pull the key out., just an idea.

 

Ok, my battery is not at 12.6 volts its more like 12.35 after having the boot open with the interior lights on for a few minutes. how do you get a battery to have 12.6v or above , its charging in the 13's and this thing is not old, or do I have a parasitic drain?
Sorry I'm not an Electrical Wizard. Still learning.
It had 12.64 volts off the charger, and when I installed it it dropped to 12.4 something. but all the Interior lights go on when the trunk is open. does that seem excessive?
Do I need a better battery? I did not buy the cheapest battery

 

Excellent question, but I'm unsure of the answer. I'm at a disadvantage trying to answer with an early model, as they don't have the same problems with low prestart voltage as with the 2003+ models.

From what I gather, the magic 12.6v minimum is something of a conundrum. My hunch is this value is merely a reasonable approximation for system voltage to remain above the actual critical minimum for the parking brake module when the starter is engaged. It is perfectly normal for battery voltage to drop close to 10.5 under the massive current flow to power the starter.

Extrapolating a bit, if we say 12.6 prestart means 10.5 with the starter engaged, then maybe 12.4 prestart equates to 10.3 under the load of the starter. Perhaps that slight reduction is just enough to make the parking brake module misbehave. Please remember this is all conjecture on my part. I'm not sure where this 12.6 minimum originated. I don't know if it came from the service manual or wherever. But it's a lot easier to take a steady prestart voltage reading, versus trying to catch a transient minimum with the starter engaged.

So how to take that voltage reading? I've often wondered about that myself. Open the trunk and the lights turn on, which will drop the voltage slightly. I think just unlocking the car awakens some modules, which further aggrevates the problem. What's a guy to do? Two thoughts:

1) Hook up your voltmeter to the battery the night before. Use some tape on the trunk switch to hold it retracted, so the car thinks the trunk is closed. Then you can leave the trunk open. Or position the meter outside, and carefully close the trunk on the meter leads. The seal should compress enough to prevent any damage. With either method, you can observe the meter without doing anything to wake up any modules or turn on any lights.

2) Forget about the meter and leave a charger connected all night. In the morning, start the engine and then disconnect the charger. This should keep the voltage up during the start cycle. If the parking brake now behaves itself, you'd know low prestart voltage was the culprit.

 

As Karl lurks for another battery issue to add to his list.

 

I think the EPB (Bowden?) cables and its motor and any other moving parts get dirty (who maintains/replaces them - hardly anyone). This means the current required goes up and that means the battery may not be enough. I'm not convinced that specifically 12.6 is required, but at some point there's just not enough to make the EPB system work.

Non-moving or part-stalled electric motors draw far more current than ones just turning freely so I expect the EPB module watches the current. Very likely it looks at that current over a fairly small time and decides whether all is OK or not.

(This is quite like the way the module controlling an electric window detects an obstacle and stops the window moving.)

BTW, a low voltage results in less current (bear in mind Ohm's Law)

 

I'll try this. Thanks, Its alright to start on the charger? I have read somewhere its best to charge the battery not hooked up to the vehicle. but what do I know.

 

I guess I should add I'm getting a weird beep when i turn the key. Also a "cannot apply park brake" warning. I had to drive it to work today with a constant beeping (same beep as when I turn the key, but non-stop if I'm moving). drove me crazy. didnt have a choice as it's my only transportation in the winter, cant ride the bike.

 

I found a service bulletin, possible fix but it software again, I have tried the re-calibrate to no avail.

Tech Says, "There are some service bulletins as well as a recall on some. The parking brake module may just need to be re-calibrated. Before you go and have it towed for any software updates, (as per bulletin) try this".

REPAIR PROCEDURE: RE-CALIBRATE THE ELECTRONIC PARK BRAKE MODULE
^ Switch the ignition 'OFF'. ^ General Procedures > Battery Disconnect and Connect, and disconnect the negative battery cable. ^ Connect the negative battery cable. 1. Reset the Electronic Park Brake (EPB) module: 2. Start the engine. 3. Firmly apply and release the footbrake five (5) times. 4. Confirm that the message 'NOT CALIBRATED' or 'APPLY FOOT AND PARK BRAKE' is displayed on the instrument cluster message center, indicating that the parking brake is in calibration mode. 5. Lightly press the footbrake pedal. 6. Apply the parking brake by using the EPB switch. 7. Release the parking brake by using the EPB switch. 8. Release the footbrake. 9. Confirm that the brake warning lamp is no longer illuminated on the instrument pack and that the NOT CALIBRATED message is no longer displayed in the message center. 10. Apply and release the EPB five (5) times to ensure no error is present, tech says, "If that doesn't get it to release, then it is a software problem and would have to be done by the dealer, I hate to have to say".

Here is what the service bulletin says,

Brakes - Parking Brake Won't Release
NUMBER: JTB00044
MODEL: S-TYPE, XJ
DATE: JULY 12, 2007SECTION 206-00

Parking Brake Does not Release
CONDITION SUMMARY: LOW VOLTAGE BLOCKS PARKING BRAKE RELEASE

Cause: The parking brake module is sensitive to battery voltage below 8 volts for more than 20 milliseconds. When a vehicle has been left parked for some period it is possible that this threshold may be reached.

Action: Should a customer express concern, re-configure the parking brake module to the new software level to resolve this issue using Integrated Diagnostic System (IDS). Follow the Repair Procedure outlined in this bulletin.

PARTS: No parts required

 

Ah, very interesting. I had not seen this specific limit cited by Jaguar.

8 volts is VERY low, and a good battery should never drop this low even with the heavy load of the starter. The typical low limit for a battery load test is about 9.5V, preferably 10.0.

Lots of possibilities here. As Jag V8 has suggested, some (or all) of the equation may be mechanical. If the parking brake actuator has to work extra hard, the voltage sensed by the module could drop to the magic 8v limit. Voltage may read okay at the battery itself, but be low at the module. The wiring to the actuator may not be adequate for excess amp draw, and low voltage results out at the end of the circuit.

I would suggest a two-pronged approach. Take care of any possible mechanical causes, such as binding cables. Just that could cause the actuator to have excessive amp draw.

Make sure your battery is in super duper condition. My latest hunch, subject to wind direction and my medication level, is the battery may not be able to recover quickly enough after engine start. You've just put a heavy load on the battery (starter engagement), and before the battery can catch its breath, the parking brake actuator is commanded to run. Throw in a little mechanical binding, and this second hit is just too much. So perhaps the battery just can't handle two heavy loads in quick order. The battery may test fine at the store, but maybe that test protocol isn't designed for this scenario.

I hate to say just blindly replace the battery, but that has been a common fix. I bet you're looking at a combination of a slightly worn battery and some marginal binding on the mechanical side.

For the battery side, I've suggested starting the car with the charger still running, for troubleshooting purposes. Unless the manual specifically forbids charging with the battery still connected (not aware of this), you should also be fine to start with the charger still energized. If you're hesitant to blindly take the advice of some random guy on the internet, you could always disconnect the charger immediately before starting, and hopefully the battery voltage should stay up there.

If you confirm a battery voltage issue, further troubleshooting is warranted. From the voltages you reported earlier, it sounds like your charging system is okay. However, keep in mind if making multiple short trips during cold weather (heater on high, headlights on, seat warmers on, etc.), the charging system may not be able to keep the battery at 100% capacity for the next start.

 

Yeah I think you guys maybe correct..

I spent the night in the garage last night, pulled off the wheels to make sure everything was mechanically ok. seems the cables are alright, yanked on them a little made sure they were not broken, tightened or loose when they weren't supposed to be, e-brake is working ok hot wired to make sure, and I mean OK ,by its working...whats going on inside the motor I have no idea.
I also took apart the manual switch by the cup holders and cleaned it up...just a check.

I ended up hot wiring the e-brake back and forth about a dozen different times with with the unplugged module harness, if you move the motor too far by holding the pos+ wire on too long it makes a clicking noise, It does not seem to like it in this position for re-calibrating, so I found. I had to power the motor back and forth a few times and left the brake released (or in like when you would change pads), and then the neg- battery terminal off for 10 min and then did the re-calibration as soon as I hooked the battery battery back up...I got the park brake calibration to take the second time I tried this, and the light went off, Woohoo. The manual switch is also working also. I left the brake released overnight by holding down the button when you take the key out (just learned about this)... its was 8 degrees F this morning so didn't want to chance it. I charged and maintained my battery overnight and got it up to 12.73 and started it up immediately after I took it off...no faults or anything but I did have the brake off already, it was 8 deg F and I didn't want it to mess up.
I think I'll keep It on a maintainer in the winter time, to help with that cold start in the morning. I'll try to get someone to help me with reading some voltages when starting the car and the parking brake activating to see whats going on, too cold right now,

I appreciate the time you have spent replying to me, taught me a couple of things! I'll see what happens in the next few days. Cheers.
Thank you also JAGV8

Oh and does the cable normally rub on the front of the fuel tank? the cable has a rubber tube on it to protect the cable/tank.

 

I stop my car's EPB applying a lot as I mostly park on the level and the parking pawl is plenty. I figure less use means it'll last longer before problems.

 

Once again, very interesting. The pattern we've seen is this problem is worse during cold weather. I think that's a combination of several things. The cold affects the battery, so the prestart voltage is lower than during summer. The starter typically has to crank longer, too, which further drops the voltage. Also, any lube in the actuator and cables would tend to gum up, causing the motor to work harder and draw more amps.

Sounds like you've already looked at the cables. You may want to consider disassembling the actuator and give it a good cleaning and lube. Perhaps some moisture has collected there and frozen, and the motor has to overcome this extra friction. This thread shows what the innards may look like. Note the rust stains, indicative of moisture:

https://www.jaguarforums.com/forum/s...r-apart-53753/


.


On the electrical side of the equation, I like your idea of using a battery maintainer. I'm always leery of suggesting a new $200 battery, but if all is good with the use of a maintainer, that's probably where you're end up eventually. A new battery at this point isn't a wild stab, it's a reasonable guess based on forum experience. It all depends on the value of your time. I'm as guilty as the next guy of troubleshooting too deeply at times, so it all depends on your priorities. You may have reached the magical point where it's time to start making futile gestures and see what happens.

You've seen the scorecard thread, haven't you? My apologies if you've missed it, but I thought you had mentioned it:

https://www.jaguarforums.com/forum/s...attery-193787/


A few other thoughts, offered for free and worth every penny:

Before engine start, try limiting the electrical load and see if that helps. If you can keep the voltage up by a small amount, that extra margin may be all you need. For example, if you normally use the auto function for the headlights, turn them off until after start. Same with the seat heaters, HVAC, and any thing else that powers up automatically. Set them all to off before start and see if that helps. Try this for a week or so to see if there is any improvement.

That service bulletin to reprogram the parking brake control module? This may be worth considering, but at the same time, all had worked okay previously. Something changed and now you're getting the fault. You could have the fault trigger level raised by reprogramming the module. However, it's possible this was already done. Can the dealer tell you by VIN? Is there a charge just for looking this up? And how much to actually reprogram the module? As cheap and lazy as I am, I'd want to return the car to the previous condition when all was good. If the dealer was going to charge me $100 for reprogramming versus spending $200 myself on a new battery, I'd lean towards the latter.

Check out the wiring diagram, figure 05.2 here:

http://www.jagrepair.com/images/Auto...cal-2005on.pdf


Note the two power sources to the module. I'm wondering if we can remove power to the actuator and leave the brake off for now and see what happens. You can't just disconnect the actuator because the system needs to see the position feedback.

The top wire in the diagram (#87 inside a box) goes to fuse F20 (10 amp) in the primary junction box (US passenger footwell). See figure 01.3. This same fuse branches out to many other circuits, so don't touch this one. It's a relatively small fuse feeding many circuits, so I think this is power to various control modules.

The next wire down (#44 in a box) looks like the one powering the actuator. It is fed by F35, a honking 30 amp fuse in trunk. See figure 01.2. Nothing else is powered by this fuse. I'm wondering what would happen if you released the brake actuator and then pulled this fuse. If I'm guessing correctly, the brakes should stay released and the feedback will still be active. I'm not sure how "smart" the feedback circuit is. I don't know if it is fairly dumb and will be happy just seeing the brakes off, or if it is smarter and wants to see the actuator apply and release with each drive cycle. Wouldn't hurt to try, though.

 

One more thought:

Let's say you have everything connected as normal but find yourself stranded because the parking brake won't release. How about this idea to get the voltage up? Run the engine for a few minutes, with the RPM around 2000 or so. The idea is to let the alternator hopefully top off the battery. As previously suggested, also turn off the lights, HVAC, seat heaters, etc. The idea is to reduce the electrical load while also getting maximum charging.

Then shut off the engine briefly and restart, with minimal electrical load. With any luck, that little bit of charging would have been enough to let the parking brake module power up normally.

 

Any updates? I can only hold my breath for so long...

 

Yeah Its working alright now that It has been on a battery charger/maintainer. Also when It was working briefly(no fault) the other day I noticed after I had got it working and started the car the fault came up about 5 -10 seconds after I had started the car, so its possible the battery is getting a little drained on startup.

I do notice it has to charge for a little under an hour every night to top it up....I haven't really been using the e-brake much now that I know you don't have to use it everytime. I have been trying to shut off accessories, the front and rear defrosters come on automatically, cause its cold I think. but keeping the battery topped up seems to help...I might try for a slightly better one next time.
I have a Duralast Gold from Autozone 1000 crank amps, and 900 cold so she's beefy, a year old and I think the battery before that (different brand) had the same issue last winter, slightly low voltage, no parking brake issue though last winter.

Have not tried pulling the 30amp fuse in the trunk lately, only earlier to see if I could get rid of the fault.
Have not talked to the dealer about the history either, I tried but they never got back to me...the car had one owner all serviced at one dealership, thought it would be no problem.
Drivers side seat never used because it doesn't work. Passenger is good.
I've got an Issue with my left front indicator working intermittently, mostly NOT at the moment. And my high beam is not working, so maybe I have a short or something in the harness, works when i wiggle it. high beam not working at all. swapped bulbs to make sure. I remember reading that the dealer has a fix for this (some kind of service kit for the harness), but I cant seem to find it anymore.

Think I'll pull the actuator apart this spring and clean/lube it up like you mentioned. looks like a fun job.

Thanks for the Wiring Schematic
sorry for making you hold your breath so long.

 

Glad to hear you're making progress. Since all is good when keeping the battery topped off, it's safe to say the issue was primarily due to low prestart voltage.

Re: Duralast batteries - From other comments on the forum, I'm not overly impressed by them. And from another forum I frequent (old Ford pickups), Autozone's Duralast starter relays are VERY problematic. No matter how wonderful the warranty may be, I'd recommend trying another brand of battery. Myself, I am very partial to NAPA Premium.

 

Did you have any codes in the abs or instrument pack modules or park brake module