For the second time in the last 9 days the LCD screen has locked on me. The Jaguar screen saver is showing and no other functions work.

Last week when this happened it took the local dealer over 6 hours to wipe all the software and re-load it.

Does anyone have any suggestions???

Tom

 

Yikes....sorry to hear that. Hope you didn't get a lemon. I had a frozen screen early in '08 but since then it hasn't returned. Turned off the engine...have it sit for 1/2 hour and it was working again.

Wish I can help....maybe email/PM Jagtech or Brutal or any other techs here on the forum for their opinion or maybe try to bring it in to another dealer? Just some thoughts......

 

Screen will lock up intermittently if the battery is a bit old - low voltage during cranking messes with the electronics.

A new battery fixed my issues - now I just need to do enough miles to keep it charged...

 

When I had the car at the dealer ten days ago I suggested the same thing, they claim the battery is "newer" and checked out fine which is why they went through the whole software update procedure. I can't really tell the condition of the battery or even see the top of it for any manufacture or date info the way its installed in the car. All I know it's completely black with visible markings.

Is the what the OEM battery looks like?? I'll spring for a new InterState battery if this is the OEM.

Tom

PS: A Corvette buddy suggested I disconnect the battery and see if that doesn't "reset" the car. I'm just not sure what cable to disconnect - the negative or positive or BOTH?

 

I put in a new Decca AGM battery a couple weeks back. My drivers side mirror would not hold its memory position. Before they would replace the door module (under warranty) I had to replace the battery. The said it was only putting out 11.5 volts. I was experiencing some other issues with the throttle (hesitation) as well. I replaced the battery with a Decca which they had at the dealer. I also believe the Absorbed Glass Matt batteries are superior to the simple lead plate ones.

After replacing the battery they determined the door module was indeed bad and replaced it. But since the new battery was installed my throttle hesitation is gone. The starter also turns much faster now when the car starts (which makes sense since the battery is fresher).

It's obvious that these cars are *very* sensitive to the voltage level of the battery when the car is not running. I imagine that there is also a heavier load on the battery with all the electronics maintaining their idle state.

I intend to have the battery checked every year at least, possibly more often just to head off these weird issues with the electronics.

 

My buddy was able to remove the Negative cable to the battery and after a few minutes re-connected it. It FIXED my locked HU and I was surprised the only personalized settings it lost were the drivers/passenger memory settings all my radio, SIRIUS pre-set were intact.

We were unable to get a look at the top of the battery to determine if its OEM or new.

I'm still trying to find out how to tell what the OEM battery looks like and what kind of markings - anyone?????

Tom

 

My OEM battery (08 XKR) was black but it had a Jaguar part label on top and a tiny VARTA label.

 

Thanks, the body is all black. Guess I'll borrow a make up mirror from my wife to get a look at the top of the battery, unless you know of an easier way/method?

This could be as simple as the 40 month old OEM battery going south.

Tom

 

I can not see the relationship between replacing the battery and the hesitation. The hesitation would show up only when the engine is running, which means that the alternator is running. The alternator, if working properly, will output a regulated voltage that would "mask" or "hide" a weak battery voltage condition.

Albert

 

These cars save data to volatile memory. If the battery voltage drops low enough such that the volatile memory is not refreshed properly, this could result in a loss of data while the car is not running. I know one of the computers (in tranny? not sure) is responsible for learning the vehicle is operated over a period of time. If the data stored from that procedure is lost or corrupted, that may invalidate the ability of the computer to adequately adjust the operation of the transmission.

When the car is off, the potential at the battery is the max potential in the cars circuitry.

 

That could be true and I did not think about that possibility. In most cars the volatile memory is maintained at extremely low voltages, down to the range of 8-9 VDC. Thus, in most cases, you should not be loosing data at voltages that are slightly low, in the 11-12 volt range. But, again, I do not know what that level is for the Jag's memory. I sure hope that it is not that low.

Albert

 

Well, when I had my door module/computer replaced the Jag tech said the battery had to be able to support 11.7 volts constantly or he would not even try and reprogram or replace the module. And to make sure the module simply wasn't losing it's volatile memory, the battery had to be replaced. Turned out the module was indeed bad, but like I said, before I replaced the battery the car would lurch sometimes after I pressed the gas after hesitating a half second or so.

Since the new battery - smooth as silk just like it is supposed to be...

 

Wow! 11.7 volt constantly? I'd like some other Jag mechanics to chime-in on that question. Seems way too high of a voltage to constantly maintain. It will drop quite a bit below that on a perfectly good battery during engine starts while the starter pulls several hundreds of Amps from the battery.

I guess that would be a solid argument for using battery tenders for cars that sit around for any length of time (not daily drivers).

Albert

 

A large voltage drop would only be facilitated by a large resistance like an open circuit in a starter, or something similar

V = IR

 

The large battery voltage drop would be the result of the large starting current, not the high starter resistance. If you had a high resistance starter you would not be able to draw the current needed to crank the motor. If you had an open circuit in the starter, the current would be zero, no cranking, at all.

Let's say, you start with a normal battery voltage of 12.5 volts. The starter for a V8 engine can easily draw 300+ Amps while turning the high compression engine over. So, starter winding resistance would be roughly 0.04 ohms.

R=V/I - R=12.5/300=0.04 ohms

The battery terminal voltage drop would be:

battery internal resistance(R) x 300 amps(I) = about 2 - 3 VDC.

Albert

 

You are talking about the starter circuit. Newer automobiles (and even most older ones) as well as any advanced electronics circuits have voltage regulation circuitry. You don't expose the whole of the starter circuit to the rest of the cars electronics (electrically); the starter circuit is electrically isolated from other circuits.

If your intent here is to win some kind of debate then that's fine - you win. And especially in the case of these Jaguars, you're talking about advanced electronics design.

My degree is in computer engineering which included a minor in electrical engineering, so I am not totally clueless when it comes to these things. Just so you know I am not just Googling this stuff...

As far as the voltage level for the Jags electronics/memory are concerned, I think it's been proven that they are very sensitive to lower voltages at the battery.

 

Sorry if you think that I'm here to win a debate. I simply read something that I thought was incorrect, and I still do.

I appreciate your degree; in response to that my degree is in Electrical Engineering, specializing in utility transmission level protection schemes. I also deal with battery technologies, as lead-acid batteries in power plants and sub-stations. Still, as it seems, neither of us are expert in auto electronics, which can be a different animal, altogether.

Just to confirm my numbers, just a few minutes ago I went out to the garage and placed an analog DCV-meter across my fully charged battery and started the car. The voltage dropped from an initial 12.5 VDC to 10.5 VDC in about 2 seconds, by which time the engine fired. It would probably drop an other 1 0 1.5 volts if it had to crank longer.

As to the starter circuit being isolated, that has not been my experience. Again, I'm not an auto-electric expert but, worked around auto electrics quite a bit for decades of racing (building/maintaining my own race cars and engines) and fixing my own street cars. The voltage regulator, IMO, does not regulate to hold up the voltage. It rather tends to regulate the high alternator output voltage down to battery charging levels. In order to hold up the voltage you'd need to have some kind of voltage storage device, something we use commonly in our protective relaying schemes to allow proper relaying after the transmission line voltage goes dead, due to a problem. Yet, the large, electrolytic capacitors we use only hold up the voltage for a very few cycles to allow the relays to trip a circuit breaker(normally done under 5 cycles).

Again, I'm sorry if this comes across as a "debate" it is not intended to be one. More like, if there is something new to learn, I'd love to know it, which is why I was suggesting in my last post that maybe one of the resident Jag experts could chime-in. I do not trust the opinion of a single Jag mechanic as they are generally not considered experts in electrics or electronics. Flying by my seat-of-my-pants senses, I'd wager that the Jag electronics will hold data far lower than 11.7 VDC. If not, than Jag is really screwing up. There is absolutely no reason to set such tight parameters for the power supplies. Most newer electronics (microprocessors) power supplies have super wide input operating voltage ranges these days; example: a microprocessor controlled relay (a PC, in itself) that was designed for 125 VDC power has an input range of 48 - 150 VDC.

Many auto shops use a small 9V battery that they plug into the cigarette lighter to hold up voltage for the computers while changing batteries. Where did I find out about that? Well... I just had a very irritating experience smog testing my motorhome in which I changed the starting battery during this past winter. I passed all the smog criteria but, flunked the computer test, as it had not reset yet after the battery disconnect. I was forced to drive it over 300 aimless miles, wasting time, gas, polluting the air, just to reset the computer in order to pass the smog. The owner of the smog shop told me about those 9V batteries that auto shops are using for that very purpose. I'll be sure to use one next time I'm changing batteries.

Albert