www.jec.org.uk

Having been through the battery drain problem, see the other thread, and assuming the warning on the information centre was related I finally got to take the car out this morning....

Fully charged battery and the restricted performance and the CEL are on display..........

Did a lot of miles and a number of engine off / restarts whilst still warm as I went about my business.... no change, even treated it to some fuel....

The annoying thing with this is the fact that it was fine when it went into the garage but showing the problem when it came out after a couple weeks hiding away.

Looks like I will have to invest in a code reader to find out what is going on.....

I presume there is no way to find out what's causing the problem without one??? number of flashes on warning lights type thing

The cheapest way into basic code reading is via a free phone app like 'Torque' and a cheap diagnostic plug (less than £20). You can pay more for increasing levels of sophistication, Bluetooth, reliability etc. as suits your pocket. Mike.

Be careful what you buy

X100's to MY2002 (I do not know about post MY2002) are not OBD2 compliant (MY2002 has a OBD2 Socket but OBD2 only Readers / Software do not work)

AllanJ

This is what I was considering

http://www.ebay.co.uk/itm/321623568050? ... EBIDX%3AIT

Tonight, I decided to take the car out of its naughty corner of the garage and take it on a run.

I started it up, the "restricted performance" in the info centre had gone but the cel was still lit....

Went off up the road, around 20 miles, to meet some other people..... cel lit all the way but no restricted performance.

Few hours later set off home, fired the engine, no cel light, no performance restricted info all back to normal........

Booted it all the way home.........showing "not a lot to the gallon" information...... BUT NO CEL OR PR info...

Brilliant.... but why???

On the downside, when I got home I couldn't open the ashtray cover to get my house keys out jammed shut.

I can't recall if you have commented about the quality and age of the car's battery on previous threads but these symptoms have all the hallmarks of battery 'weakness'. In any XK8, battery condition is absolutely critical, not merely important! If the battery is of the correct spec and is more than 3 years of age, it is a suspect. If the battery is below spec in any way, it's simply not worth continuing with it. Either try borrowing a new or youthful battery from a fellow member locally to see if all the warning lights disappear or invest in a new one simply to eliminate it before chasing any remaining symptoms. Mike.

Hi Mike and PTR,
I realise it is not in this actual post, but PTR's battery was new in Nov 14 and I also know that that doesn't rule out the possibility of it not being 'up to scratch' . Judging by the figures posted by him regarding voltage before during and after charging, it doesn't look like a bad one and I doubt that the supplier would give a replacement under warranty with figures like that as it would show up good on one of those awfully rough drop tests.
Not sure how I would proceed with this one, £100 for a new battery seems a waste at this stage - how many other batteries have been wrongly condemned. Even the Jag diagnostic equipment seems incapable of pinpointing the EXACT cause of some of these error messages and chucking lots of sensors etc at it can be an expensive option for all but the company backed cars.

PTR

I agree with Orkney, the battery seems in good order. The make is not one the Car people use but has been around the Bike world since before I started riding bikes (over 40 years ago) and I've never had trouble (when under 3 years old) with them in the past. However, my XK8 does suffer from reduced voltage after short journeys / little use (9 months old Varta 110ah).

The light & messages would lead you to believe that there is an outstanding problem that has been identified during the 'starting up procedure' a trip to someone who understands the X100 electrics is the order of the day.

AllanJ

Thanks all, for your comments.
As Orkney says the battery was new in November and on the current draw thread I did do some checks which leads me to believe the battery is indeed a strong one.

I have just been out in the car again today, around 40 miles,with no sign of the error messages or cel.

I really can't understand how these spurious messages, trac,gearbox,restricted etc can come up on the basis of a battery voltage fault.... surely the Jaguar engineers could have put a "battery Low" warning in to the system?

Right at the top of the fault priority ranking should be "battery low" if that is indeed the fault that is the cause of the problem on the cars that show oddball messages, not a stack of TOTALLY unrelated messages... .
.. no wonder the diagnostic equipment gets a tough press for failure to ACTUALLY diagnose error messages correctly.....

Anyway, the good news is I am enjoying the Jaguar Experience, once again

Excellent news.

One has to look at the age of the electronic architecture on the car which is quiet ancient now. The same with my own S-type on a similar 1999 design platform cribbed from the XK8. Such electronics were cutting edge in their time and I suppose issued onto the market in all good faith. Nowadays current designers would probably see the design as rather agricultural when set against newer designs. It may be that the design which gives us such frequent nightmares is not that sophisticated and there is indeed little in the system which can cope with low voltage situations and little control over what can occur in such a situation.

The most common low voltage scenario I have seen is DSC faulting when a battery is low. Interestingly repeated faults such as the ones I endured with a duff TAC module on a throttle body, can stack up on the vehicle computer to a point where a car comes to its knees! I`ve seen that on my S-type several times and cleared the accumulated junk returning the car to some semblance of normality. Ultimately the throttle was replaced which put an end to the misery.

Diagnostic gear points in the general direction of a fault. That appears to be an issue, say with the coolant sensor may in fact be just down to plug and socket corrosion which is easily fixed. What clouds and frustrates the issue sometimes is that other faults suddenly crop up alongside the true cause and appear unrelated to the cause itself. One of the things I learned at a diagnostics seminar is that a signal feed to one component may have spur joints in the cable which can fault and so any other part on that feed line may also appear to be in difficulty. Diagnostics is an exacting science often needing vertical and horizontal diagnostic skills. Some of us, including myself are not that well versed in that respect and can achieve a limited and reasonably useful response when we plug in our diagnostic magic box. Others here are rather more proficient and have managed to use a diagnostic machine, read electronic diagrams and even grub around in the right locations to fix quite obscure faults. My hat is off to them.

I`ve always found a car with a good battery is what keeps the ills away. I must admit to struggle with my car on occasions as it does so few miles and regular long distance charging does not figure too often. So I end up with discharged batteries through infrequent use and often the odd MIL lamp or other issue to deal with. I`d suggest a solid new battery and frequent use is probably the best way to help deal with these problems as a line of prime start. Well used cars in my opinion make for happier runners electronically speaking.

In effect my take on the matter is very similar to that of Mike H.

Mike K

Hi Mike K.
I Pal of mine turned up in his smart new XF diesel to talk about tow bar electrics.

What I did notice is that it has two Batteries. I cannot remember , but think the large battery was what we would expect, like S type, and the small battery was about an 8inch cube.

I just wonder what the thinking is for that arrangement! We know that the starter motor takes a pretty hefty load for normally only a brief moment to start the engine. We also know that battery voltage drops quite sharply during that process.

As you have suggested a million times, the electronics on these cars is very sensitive to voltage, so is this a devious method of protecting the micro processors and the like from the savage attack of the starter motor and other heavy loads.

Of course there may be a simple explanation for this arrangement that I have not caught up with yet

Any comment

Oldtimer

PS Perhaps I should just stick to rusty sills and the like!

That's a strange coincidence! PTR and I have been discussing this very question about giving the delicate electronics a supply of their own to prevent these spurious error messages. Almost everyone I know with a post 97 Jag or Daimler has these messages from time to time - even the regularly used ones. Some have spent a small fortune using dealer diagnostics to track down elusive and frequently mis-diagnosed faults. The thing that annoys the HELL out of me (and PTR) is that an apparently low battery throws up all manner of useless info on the display. Was it beyond the wit of man to have the message 'Low Battery' as the first level in the architecture? If I was cynical I might think it was a deliberate ploy to part me from my hard-earned. Thankfully I wasn't born cynical, it only started when I was about 6 months old.

Now when I was a boy, cars used to have a gadget which did that for you on a constant basis. What was it called? ...A dash mounted VOLT METER! Yip. I feel sure that was what it was. Why, oh why, did they take it away? I really do miss having one. Out with the hole saw set I suppose and retro fit.

Mike

Yes, your memory is spot on, a voltmeter it was (XK's have them though), but I think it might be a bit like adding wicks to the headlights. I very much doubt that Mr Smith's old 2 inch meter with a wobbly needle would be able to differentiate between 12.6 and 12.3 volts. Oh,and by the way, you might get a nasty surprise if using a hole saw on a Jag dash - the very thin veneer is applied over an aluminium armature.

You are quite right, Mr Smiths 2 inch meter was an "about meter" about enough to do this or that, but that was all you needed. Of course my '73 XJX12 has one and has proven to be adequate over the past many years.