You may be on to something. Could be Jaguar’s taste monitor behaving exactly as designed. The car may be rejecting your alleged taste in music, as it should. Remove, at the very minimum, Justin Beiber’s Christmas album and the Beaches soundtrack. Replace with anything by Bobby Blue Bland or Richard Thompson. Let us know what happens.

 

I don't think it likes Sabbath, ACDC, Thunder etc, but I think the one that made it throw the audio DTC was the USA Driving songs cd

You know how I guessed that?
If you look at the first lot of photos I posted from IDS you can see the audio DTC showing.
Now I've removed the cartridge, when I scanned it today..................no audio DTC showing

 

Must be speaking about me.

 

So, I decided to do a little test yesterday, I had the time and wasn't needing the car for anything.
I disconnected the battery from the car and charged it on the proper charger for 2 hours.
After dis-connection at exactly 13:00 hrs, the voltage read 13.21 volts, obviously showing the residual charge.
Here's the rest of the results:

13:00hrs = 13.21v (residual)
let battery stand for 1 hour
14:00 = 12.73v
15:00 = 12.69v
16:30 = 12.66v
20:30 = 12.62v
08:30 (this morning) = 12.58v

So a loss of 0.15 volts over an 18 hour period with the battery OFF the car.

The reason I did this is to try and isolate whether I have the onset of a battery problem or a quiescent drain problem on the car.

Given that my battery voltage drops by double that (typically from 12.3v to 12v)(I know that's on the low side, it's just what I've observed lately) if I leave it attached to the car without the tender on it, I'm wondering if the combined (possibly) failing battery and cars own "keep alive some things" is enough to have caused me the original problem of my engine failsafe warning.

This is where I now need the technical expertise of the members on here please.

Would someone be able to tell me what the expected voltage drop should be over a 12 hour period if the car is in a "normal" state?

By "normal" state I mean no drain problems, good battery condition, car goes into sleep mode and shuts down things as it should and keeps others alive as it should.
I'm having a browse through the forum now to see what I can dig up, but there is SOOOOOO much on batteries and drains...........

 

You've effectively tested a battery with no drain when you at least wanted the spec (say 30-50mA).

So your battery may or may not be defective - still inadequate data.

There are threads about the car's quiescent current and maybe you could measure yours...

 

+1 on that.

This got me wondering if you could rig up the disconnected battery with a fixed drain in the 30-50mA range. Maybe something like an LED bulb or who knows what. Leave that for a few days to simulate normal drain when the car is in sleep mode.

Now THAT would be interesting to see. Using a fixed external drain would eliminate any intermittent onboard drains. I vaguely remember another forum member found some module (seat control?) periodically waking up and slowly killing the battery. Unless you were watching the meter exactly when it happened, you'd never know.

The gauntlet has been thrown down.

 

Pulled the trigger on a new battery, Exide EA1000.
Manufactured 10 weeks ago according to the date on it.
3 year no quibble exchange warranty.

I have had it on a slow charge for the last 5 hours so it is now topped up and fully charged, will fit it in about an hour, measure the voltage before locking up for the night, then check voltage again in the morning before work.
We'll see where we go from there.

 

And it just so happens that I have some led bulbs in stock, and with tails already on them as well, the type that are used in motorcycle dashboards for the high beam/indicators/oil lights.
Gauntlet picked up.

 

I've got a lab coat and clipboard. I'll catch the next flight if you don't mind picking me up at Heathrow...

Do you still have the old battery? It would be REALLY interesting to compare the two.

 

For 50mA at 12V you need 240 ohms (or somewhere close).

It'll dissipate about 0.6W so don't use a typical 1/8 watt electronics-type resistor.

A 1/2 watt 12V bulb would be fine.

 

Right then, it's all going over my head now
I still have the original battery.
I have bulbs and wires and a multimeter.
A couple of chargers.
Knowledge of milliamps and how to measure accurately eludes me at this point.
But sleep does not unfortunately.
Work in the morning so I'm off for now, but please feel free to give me a write up of how you would like it to go forward.
I have cables hanging out the back of the car at the moment so I can check the voltage before I press any buttons in the morning.

 

My thoughts are to test the battery by itself under a 30-50 milliamp load, to simulate normal current draw of what you should see after the car enters sleep mode. Please keep in mind this doesn't test the car's circuitry at all. It's just testing to see how the battery would behave if the car was behaving perfectly.

I'd like to test the battery separate from the car. If the car is NOT behaving as intended and is excessively drawing down the battery, you wouldn't really know if the car or battery (or both) was at fault. With my test idea, we're eliminating all possible external influences. Now this is going to drag out the process to give the car a clean bill of health, but I'm okay spending your time like this.

I get it. This is from the "How Many Angels Can Dance on the Head of a Pin" department. For the quickest fix, replace the battery (as you've already done) and run the quiescent drain test referenced earlier. But some of this is just fun (at least to me), to get an idea of how a battery will behave.

The idea is to take voltage readings at periodic intervals, perhaps every few hours or so. Ideally you can run this test over at least a week, to simulate a battery powering the car in sleep mode for an extended rest period. If the battery fails this sleep simulation, then it would have also fail if installed in the car.

You will need a multimeter capable of reading milliamps so you can set up the test drain on the battery. Once you get the test drain dialed into the proper 30-50 mA range, you can use the meter to read the voltage.

Here's a good video explaining how to set up to read milliamps:




What brand/model meter do you have? I might be able to find a video with the same meter to make it easier.

Your battery must be fully charged, so use an automatic batter charger if you have one. Let it run overnight until the charger says it's done.

Start by setting up the meter at the highest amp range, as explained in the video. We're going to start with the meter's highest range and then work down, to make sure we don't overload it.

Hook up one of your LED bulbs in series with the meter, set to the highest amp range. Put the red meter lead on one side of the LED. Connect the other side of the LED to the (+) battery terminal. Connect the black meter lead to the (-) battery terminal. The light should glow and your meter should show an amp value. Note how all current to the LED is also passing through the meter. If the LED is polarity sensitive and doesn't illuminate, swap the LED leads.

So how much does a single LED of yours draw? Ideally, it will be 30-50 milliamps. If so, that's super easy. If more, you're going to have to find a load with a smaller amp draw. You might be able to connect two LEDs in series to cut the amp draw in half, but that also reduces the voltage to each LED and they will probably shut off and not draw any current. In that case, you can play around with some incandescent bulbs to get into the desired milliamp range.

If the current draw is too low with one LED, you can add additional LEDs in parallel with the first one to get up into the 30-50 milliamp range. If adding LEDs in parallel, please note the meter (still set to read amps) must be connected in series with the group of parallel LEDs.

Once you've come up with a test load that draws 30-50 milliamps, you can remove the meter and connect the LED(s) directly to the battery. With a test load set up like that, a fully charged battery should power the circuit for weeks. Set your meter back to reading voltage (don't forget to move the red meter lead to the proper receptacle) and record the battery voltage and time. Keep the test load running and record the voltage every few hours.

You may see a fairly big drop in the first hour or so, but don't be alarmed. That's just the surface charge being depleted. Just let the test load run and keep recording the voltage like a good scientist. Don't recharge the battery or otherwise change anything during the sleep mode simulation. Remember, you're trying to simulate how the battery would behave if installed in a car that was behaving perfectly in sleep mode.

And once you've tested the old battery like that, you can try the new battery if desired. That would be sort of a hassle, as you'd have to reinstall the old battery if you want to be able to drive the car, but I think comparing the results would be very interesting. Remember to fully charge the new battery before running the sleep mode simulation.

 

Thanks Karl, I'll have a gander at that a little later, just got in from work, mayhem as usual.
As a side note, i fitted the new battery about 7 pm last night, locked the car up as normal (double locking), checked the voltage this morning at 05:15hrs, before unlocking the car or anything, read 12.61 volts across the leads.
Food for thought................

 

Driving home, lights on, heater on, radio on, 7.5 miles door to door, back home, car into garage, engine off, did not lock it, popped the trunk, measured the voltage, 12.61 volts.
I'm probably getting ahead of myself but.............I'm liking this so far.
I shall still conduct the tests next week as Karl posted, for curiositys sake.

 

I may have to try my own test idea, also just for curiosity's sake. No problems with my Jag, but my pickup is due for a new battery soon. Maybe I'll pick up a new one a little early and run it through a long test cycle before installation. Then I could install the new one and run the same extended test on the old one.

 

Well now, I have to say I am pleased to report that absolutely nothing is wrong.
Since replacing the battery and every so often putting it on the battery tender if I'm not going to use it for a while, I've had no instances of Engine Failsafe mode or any other MIL light indications whatsoever.
Just jump in, drive and enjoying it.
Enjoyed it even more the other night when I, for absolutely no reason whatever, mashed my foot into the carpet just for the hell of it.
I do however have another problem looming on the horizon.
I'm just about to start a new job, and if things go well with the business and my input, I have been asked what car I would choose if I had the option.
Do I go for the E-Pace, the (ahem) BMW i8, Volvo hybrid.........depends on the budget I suppose but....................

 

Can't they give you money instead?

I thought the tax on cars made them (very) unattractive now.

Er... i8? Not a cheap car.

 

The salary is good enough for me as it stands, but as far as the car is concerned, to practically wipe out the tax implications you put it down as a pool car so "theoretically" any employee can drive it. Not that that will happen I hasten to add................
And yes the i8 is expensive. more than twice the price of the I-Pace if I read it right. But I do like the XJ as well.
My new boss drives a merc, all I can tell you is it's silver.

 

As I recall, you can't take it home, commute with it or use it for (say) the weekend or the tax is payable. And it's based on the deemed original new price I think (kinda rusty on this stuff).

 

My comment was no longer relevant so deleted.