Hi z,

Sorry, but I don't have an answer to your question. Not even a smart-a$$ answer, although my initial response was, "IT'S A JAG"!

My 2001 XKR behaved brilliantly the first year of ownership and then I began to get the unlock/lock cycling when unlocking the car using the remote.

That went on for about a month and then the car began to suffer the dreaded "dropping window syndrome".

As you mentioned, from reading the forum posts I knew that it was time for a new battery. Even with the new battery, if I don't drive the car for four or five days I get the cycling door locks when I first open it.

I think it is the memory circuits in the various modules that run 24/7 that eats batteries. There are also other factors that could be involved such as the little metal door in the ignition switch not closing properly when the key is removed. This leads the car to believe that the key is still in the ignition and all systems are go.

A battery tender and jaguarforums.com are a must have with these cars.


Cheers,

Stu

 

My guess is it is one of the very first fully networked cars. See the 'scholarly' design articles published on it just prior to production in '95-'96. here: http://www.thejagwrangler.com/jaguar...nd-papers.html

The first generation of any new technology usually has some rough edges. What is a bit disappointing is that some of the rough edges were never resolved in its 10 year production run,

 

When you pull the key out it makes a switch on pin 4 to 5 ground on the ignition switch attached to the key barrel . This triggers the security module to go into a shutdown go to sleep sequence otherwise the car stays alive and drains the battery called a parasitic drain although it is doing what it is designed to do , just not triggering because of a possible bad switch . Just remove the column lower panel to test this with a meter as well as verifying you have a good ground to car frame on the 5 pin of the car side of the connector . you can lube this key opening door as a easy try that is a common issue .

In the shutdown sequence certain things must be satisfied before it goes to sleep as you remove the key such as steer column retract and tilt up and seat extension positions . The way to remove those from the list of suspects in the turning the steering column large round knob from auto to off .

 

It's a (major, IMO) mistake in the design. Well, minor if you come on this site as you have done and do some reading.

With the benefit of hindsight I hope Jaguar would have put in at the least a battery monitor which put a message out saying to change (or maybe charge) the battery. Even better if it prevented other (largely false) problems due to low volts/power. But they didn't

So it is what it is.

(Yes the car does have networks and lots of computers but they're not special and weren't even leading edge at the time. Any competent electronics people could have done the battery monitor or just made the whole car far more resilient. On the plus side, the electrics are not Lucas! Overall the cars are good.)

 

Its not so much a failure of the design, but a failure to test it properly. Jaguar never thought to put in a 5 year old battery and combine that with some loose/dirty connections and then see if it all still worked after leaving the car standing for a week.

We shouldn't really complain though, because its a lot better that the car starts and runs (albeit with faults) rather than refuses to start at all because the computer has decided that the battery needs to be replaced.

 

Lady Penelope great post. I have heard of this problem before and you explained it well.

Because of recent snows over here in the UK I could not drive my car for a couple of months and when I did try and start up it seemed a little 'sluggish' but start up it did. However I had all sorts of problems. Doors, locks, windows etc. Turned out to be the battery.

Having heard a lot about these CTEK battery chargers I did some research and ended up buying one. A very good investment. I got the 'MXS 5 Charge and Test' model. These de-Sulphide your batteries, recondition them and are safe to put on the car for a long time and just leave. Personally I think they are worth the money.

If you want to know what problems I was having, symptoms etc and why I eventually went for this CTEK you might find this an interesting read. http://www.jaguarforum.com/showthrea...=1#post1084909

 

I invested in a 12 volt DC wall converter from the thrift store , couple of bucks . I'm a really cheap guy

 

But does it switch off or just keep pumping out electrons?

 

I have always used those. Got one in my garage at the moment. However if you forget and leave it on etc It will cost you!

 

We're not alone. Being an ex-Corvette driver, the C5 and up models also suffer from low battery issues. Battery Tenders are an integral part of Vette ownership, too.

 

As said above we are not alone - my Grand Cherokee with a hemi engine also doesn't like a failing battery - some posts on the Jeep forum confirmed my suspicions.

 

It turned out for me that the automatic lights setting drained the battery when the engine was off - try not using that and see what happens.

There is apparently a fix for it, but I haven't got round to it.

 

another possible issue with this, any other special use car and even regular usage specimens is that the manufacturer assumes regular use driving pattern and probably tests based upon this model. even some rather mundane vehicles going back decades and in the present write in the owner's manual something to the effect that their warranties assume that the vehicle is used x times per week driven for a distance of x for a time of x or something similar. some owners of relatively new Toyota's and Honda's encounter the issue of not passing the computer read emissions testing since the cars are only used locally. often the owner's manual of any car will state that the owner should contact the dealer for long periods of storage.

another matter is that batteries are only expected to be reliable for a period of time regardless of how well they are maintained or the usage pattern. my friends in very cold climates often replace them ever three years or so regardless of its performance as there are hard limits due to the conditions. a battery maintainer is only to prevent ruining a battery during its useful lifetime. another issue is that if a battery is beginning to become sub optimal the alternator works harder and this is more costly and annoying to replace. here is a good test, especially for cars with a voltmeter. watch the voltmeter when cranking for a cold start after an overnight. if it drops more than usual under the same conditions, time to replace. yes, i know that i just invited a ****storm from the crowd that claims ten years or can recondition . . . , however i get never less than six years from a Lead acid battery and never alternator failure. i run the recondition cycle once a year before the cold weather and if the battery was drained somewhat. for any car the maintainer should be used for more than a week of disuse. even on the XK8 voltage is still above 12 after seven days of idle regardless of temp.

my mundane 08 Honda did many of the same things as the XK8 when allowed to sit too long and the voltage dropped. not the fault of the car.

 

All of my cars except one will drain the battery if not driven for three weeks. The Avalon just did it. The Cobra is carbureted old tech and the battery will last all winter. Just for fun while reading this I went out and started it after sitting unused in its shed for 4 months since end of November 2017. Cranked it over to feed gas into the carb, pumped the gas pedal 5 times and it started. The battery is a 7 year old Everstart with an 84 month warranty, reads 12V, but when cranking, goes down to 8V. When running it went to 14.2V.
To me the biggest disappointment with new fangled computer automobiles is the fact that there is no convenient way to preserve the battery when parked for a relatively short time if there is no access to power for a battery maintainer. In the past I had to resort to disconnecting the battery in the Mustang for the winter. Rant over.

 

with boats we used 12 volt solar maintainers with excellent results. used one in my car when parked at the airport for over two weeks, worked well. make sure that you purchase a good unit that will not discharge the battery in low light. yes, some low end units can do this.

 

Thanks for that warning!

 

I think you answered the question in your header, tho I prefer the pet names 'Primadonna' and 'Drama Queen'..

 

I think the frustrating nature of these battery issues has to do with the fundamentally digital nature of the electronics in this car. With an analog car (older wired car), I suppose a low battery would give erratic injectors, low sensor readings, etc. i.e. probably not a great running car but a working car. Heck, there was a time you could start a car by pushing it! Now, most electronics is digital (as in actual code runs on a computer/micro controller), so it is a lot harder to determine whatever voltage is too low to allow these processors to even boot. Fluctuating voltages are likely even worse with modules booting and rebooting randomly. Further, some of these modules are supposed to check on the existence of one another early on. ECM must have a TCM. TCM must have an ABS/TRAC, etc. i.e. increasing dependencies through exchanges of digital messages. In short, _all_ these modules have to start/boot pretty much at the same time. If not, then oh well!

The "Jaguar" answer is likely that the battery is a wear item and is supposed to be in top shape under all circumstances. As an owner, if you chooses to take shortcuts, then you are on your own (which all of us are in anyway), and open yourself to these errors.

To my knowledge, there are already a couple of bus validations built in, but clearly not well suited to catch the low battery scenario. Things like VCATS can catch modules that physically fit on a connector, but are not suited for a particular car.

For the suitability of a "voltage checker" of some kind, I would not expect it from a car like this. This is supposed to be a luxury vehicle bringing an $80,000 experience to an (original) owner. This car does not even have an indicator of what gear the transmission is in. It is supposed to just work. If you need to know, you have the wrong car, in a way. Just my thoughts.