Hi All, I'm new here and would appreciate any help or suggestions anyone could provide for me. I'm amazed at the vast knowledge base of members here. I have a 2004 S-Type V6 with around 70k miles. Have owned the car for around 10 years and have had no major issues over the years. I'm currently having problems with the car and desperately need help! Here's the situation:

- 10/2016 Had battery replaced after car not starting

- 10/2016 Day or two later the engine light, ABS light, DSC light, (with their respective fault messages flashing and gearbox message flashing) All came on. Read here that faults/lights could be due to resets not completed after battery install

- Winter 2016-17 Car driven only occasionally (would sometimes sit for up to a week or two) and only driven locally (errors still on) but car was starting and running fine

- Two weeks ago while running errands (short drives and only off for few minutes before restarting), car won't start. Radio, interior lights still functional.

- Hours later, car started fine with no assistance. Next day brought to mechanic to disconnect battery, perform reset, and check for any codes/problems. Found nothing wrong but when car was picked up, all the lights/fault messages came on again within minutes of driving.

- Last two weeks car was driven every 2-3 days. Started and ran fine however no starting/stopping type drives. Would go from point A to B, car parked for hours and restarted fine to return to point A. (Still had faults/lights on dash)

- This Fri. running errands, after second stop of 5 mins. car wouldn't restart. Kind of cranked w/first few attempts, then wouldn't even crank. Was towed to mechanic. Checked on car later in night and it started perfectly fine w/no assistance. I used a battery load tester to take some readings (see below)

- Today mechanic claims battery is/was fine but recharged it to top it off. Claims issue was w/alarm system (no clue why) and reprogrammed alarm. Again within mins. of driving off, all of the faults code and dash lights came back *except* the gearbox one. Brought car home (couple minutes away), parked, restarted a few minutes later, drove around for 10 min. turned car off and it wouldn't start again. Tonight started fine again and took more readings. (Upon starting, engine and abs faults/lights immediately come on. DSC light/fault only appear after I reverse out of driveway and put car in drive. It goes off again when car is turned off.)

---------------------------------------------------

I read on here that Jags can be very fussy with even the slightest voltage variance and batteries should be operating at full voltage. (Tried telling mechanic this but they were insistent it's not battery.) Here are the battery load tester results (bear with me, first time attempting to do this - if incorrect, let me know and I can try again). I used a Schumacher Battery Load Tester/Charging System Analyzer BT-100

Friday after car sitting for few hours:
12.2 volts - when everything off / 11.4 volts - when pressing load switch on, car still off / 14-15 volts - when revving engine / 13 volts - car on, all accessories running (a/c, radio, lights etc)

Saturday after battery was recharged at mech.& after sitting for an hour):
12.4 volts - everything off / 11.4 volts - load switch on, car off / 14.7-14.8 - after turning car on and revving engine few times / 12.2 - load switch on, car on / 14.1-14.5 - car on, all accessories running / 11.8-12 - Load switch on, car on, all accessories on

Drove car around for 10-15 mins. parked, turned car off and on multiple times worked fine again, then stopped completely. Cranked once or twice and then only clicking or nothing. Lights, accessories all still functioning. Immediately took readings while car wouldn't start:
12.2-12.3 - car off and car won't start / 11.2-11.3 - load switch on, car off and won't start

Battery in car is a Deka model 649 MF, 900CA - Any ideas what is going on????

I can't keep driving the car worrying that it won't start or will die, wherever/whenever. I was considering brining it tomorrow to a Pep Boys to have them double check that no codes are coming up with the car code reader.
Please help! So frustrated. Many Many Thanks in Advance!!!! Best Regards, A

 

Does that battery have a vent and is it connected to a tube running out of the trunk?

I would get the correct battery first.
Pep Boys has the correct Bosch battery. That's where I got mine.
.
.
.

 

Ooh, great post. Concise history, meter readings, and so on. All these details really help. The only thing missing is your shoe size.

First thing to know: Don't panic! Your car obviously has some electrical issue, but it's repairable once you figure out the root cause. You are already well down that path.

For years I've had a Schumacher BT-100, aka The Toaster. Love it for load testing batteries, but beware of one limitation. Batteries also act as a giant capacitor for the alternator, but the BT-100 (and other resistive testers) can't test capacitance. Usually ​​​ a battery's cranking capacity drops off, requiring replacement, long before a capacitance problem become apparent. So you almost never hear of a battery failing a capacitance test, but it's still important. The simple way to check is with a new capacitance-style battery load tester. Most shops and auto parts stores have them now. They simultaneously test capacitance AND load-carrying ability. Just be aware the kid running the test likely won't realize exactly how the tester works. He just hooks up the leads, reads PASS or FAIL on the display, and then tries to sell you a battery.

So while it's rare for the battery to have a capacitance problem, you can quickly rule this out. Have it tested with the new style tester.

Did you ever have all the lights and no start before the battery the battery was replaced? I just want to make sure that's when it started.

One likely possibility is the battery ground cable has a bad connection where it bolts to the body. The tip of the bolt extends into the right rear wheelwell. Road spray gets in there and wicks up the threads and causes corrosion and a marginal connection. I'd suggest removing that bolt and cleaning up the two mounting surfaces. The whole problem could have started when this connection was disturbed as the ground cable was pushed aside when the battery was replaced.

Another thought is your driving habits don't let the battery receive a full charge. Short, infrequent trips with lights and AC running mean the battery gets shortchanged. The fix for that would be to keep it on a trickle charger. Several forum members report having to do that for cars driven infrequently. It wouldn't hurt to try that for a couple of weeks and see if that fixes the issue. I'll poke around and see if I can find details of how one member rigged up a charger connection so he didn't have to repeatedly open the trunk floor.

After that, I'd suggest troubleshooting the last known fault where the starter wouldn't crank. Here's a guide I wrote exactly for that issue, posted on a forum for Ford trucks, but the principles are the same. Wordy, I know, but the actual test only takes several minutes:

https://www.ford-trucks.com/forums/1...w-starter.html

That simple test will find electrical faults that defy all other troubleshooting.

 

This was the thread about adding a trickle charger:

https://www.jaguarforums.com/forum/s...ng-port-87362/

 

I have to check on the vent. I checked Pep Boys website for Bosch batteries and three models came up for my car. 1-Bosch Premium Performance Group, Size 49 (49-850B) 2-Bosch Premium Performance (H8-900B) 3-Bosch Premium Advanced AGM (49-850BAGM) Is there a model you prefer?

I did read elsewhere on the forum that the AGM newer technology batteries aren't good for my car. Iirc, it was something about them not working at full capacity/voltage. Do you know anything about that?

 

Thanks so much for taking the time to reply with such a detailed response and info. I really appreciate it!!

~I will get the capacitance tested. Is there a reasonably priced unit that I could purchase for future use. It sounds like it would be a good idea to have on hand. Is this something that can be tested with the fancier car code readers? For that, I had planned on investing in a good one. Any recommendations?

~Just prior to the initial battery replacement, the check engine light had come on if I remember correctly. NONE of the other fault lights and message were there until a day or two AFTER the battery change. They all appeared in first trip after bringing car home from shop. I will check the ground cable and look for corrosion.

~I had purchased a solar trickle charger (I believe it's a SunForce 5-watt panel), put it in the rear windshield and threaded the cables behind the rear folding seats but did have to keep the trunk floor up as you mentioned. It wasn't purchased until a month or so ago after winter was over and was used for a few weeks but stopped keeping it up bc a-I read after the fact that it will not charge the battery, it will only keep the charge the battery already has. (I thought battery might be already be low/ruined due to sitting longer in winter) and b-I wasn't sure if I could keep it connected while driving. Since other people in my household occasionally drive the car, it was getting annoying having to connect and disconnect it for them. It's probably a good idea to use it again but would it make my problem any worse now?

~Thanks for the link to the guide you wrote. I will sit down and read through it when I have a little more time tonight. Hopefully I can get to the root of the problem. I hate driving the car fearful that it won't start again.

~Finally, did you see any issues with the battery tester readings I listed? I've read a few conflicting things here about lowest voltage actually needed to start the car. Is my battery in as good of condition as my mechanic claims? They don't specialize in Jaguars.

 

Lots to digest.

For a battery tester, I've been considering several I've seen on Amazon. Search for "automotive battery analyzer" or similar and you will see many choices under $100.

As far as checking your battery's capacitance, my terminology may not have ideal. I don't believe there's really a capacitance specification per we. And those fancy new battery analyzers aren't specifically measuring it, either. They're actually checking for conductance, which is the current carrying capability, and the inverse of resistance. I'm fuzzy on the exact details, but I think they do this by sending a pulsed DC signal (similar to AC in some ways) through the battery and interpreting how it responds as a capacitor. On a practical level, it's a box full of magic, and that's all we really need to know. I didn't want you asking the kid at the parts store about the capacitance reading cuz you heard about it from some guy on the internet...

I've been trying to find a particular article about battery service and testing. It was from some professional organization, but I can't find it now. Lots of details about the new generation of battery testers, and how they can find faults that won't appear on purely resistive testers like the toaster. It said for a pro, the toaster should rarely be used anymore and I fully agree. I still use mine until I upgrade, but am also mindful of its limitations. In other words, if a battery fails the toaster test (remember, must be fully charged), it's definitely bad. But if it passes, it could still be bad, so passing isn't 100% conclusive.

Some of your toaster load tests look to have been taken with the battery less than fully charged. That's not a valid test, so ignore those results. One cool advantage of the new testers is the battery doesn't have to be fully charged.

Looking at your test results, I was more interested in the start of the history, and the last no start. Looks like it all started after your previous battery was dying, possibly of old age. While rare, it's possible the new battery is bad. I think it's even more likely the ground cable connection was disturbed, so check that first. And it does appear your charging system is working, but your short infrequent trips are keeping the battery from consistently getting a full charge. An inexpensive test would be to charge it every night for a couple of weeks and see what happens. Use a regular automatic charger, not a trickle charger, since one of those can't really keep up.

Do you have another vehicle with which you can swap batteries for troubleshooting? If the new battery was the problem, then you'd know. You'd have a little more ammo if you need to get the present one replaced under warranty.

 

The Bosch 49-850BAGM is correct. I don't see any problem using AGM batteries and most of them don't require venting.

The other ones will probably work too. I like bigger batteries so your 900 Amp one is slightly larger. Just get the vent routed out of the trunk. The fumes from the battery can and will cause a bunch of corrosion in the trunk area and the S Type has a trunk full of electronics!
.
.
.

 

The batteries are all right. The problem is that they need a constant charging rate over 14volts and our cars only produce that for a little while after starting and then it drops to around 13 volts. This means that we can only charge the new type of batteries to around 80% of their capacity.

If you charge the battery for 20 hours it should show that you have 12.6 volts after you leave the lights on 3minutes.
If this the case then the battery is ok.

have you checked the battery earth is connected correctly, mine once came a little bit corroded and it few up loads of problems.

 

Found that article:

https://www.motor.com/magazine-summa...tery-of-tests/

Didn't have all of the illustrations, as least in the mobile version I'm viewing, but still lots of good info about determining if a battery is up to snuff, especially on a modern vehicle.

Note this comment:

"As to the “toaster” type load testers that draw a fixed current of 100 or even 200 amps, they have no place in a professional garage."

As mentioned earlier, I still use my toaster, but am mindful of its limitations.

 

If I understand the battery voltage readings given in your first post, then you certainly have battery and / or cable connection problems. Suggest you read the "Battery 101 for S-Type Owners" listed in the Sticky HOW TO post.

Several of us did this write-up after dealing with hundreds of posts just like yours. The 14+ Volts with engine running is irrelevant other than confirm the charging cycle works. It is the standing battery voltage which is critical. Your 12.2V may (or may not) start the engine, but is insufficient to run the electronics - hence the array of errors and fault codes. The mid 11V range of readings suggests your battery needs life support! It is near dead! Perhaps it may start an argument, but no surprise if it won't start your car.

We don't need to over-think this - nor try to reinvent it - what you need is 12.6V minimum and a smart charger or battery tender for those occasions when the car spends a week or two without a good (read, "long") drive - local errands are a real killer! Rarely are "new" batteries sold fully charged, and also rare but not unknown, some have been proven "dud" from the get go.

Cheers.

Ken

 

Any progress?

I picked up one of these a couple of days ago, an Ancel BA101 battery analyzer:



For only $55, this thing is the cat's meow. Of course, after an Amazon purchase, I noticed it was available for less on eBay, so be sure to shop around. This appears to be a badge-engineered version of a generic model, all in this same price range.

Forgot to get some pics in use on my S-Type, but this shows it on my old Ford pickup:





One cool feature is this tester does not require the battery to be fully charged for valid results, unlike the old-fashioned toaster.

Even cooler, approaching Chuck Norris riding a T-Rex level of cool, is the AC ripple test for the charging system. We've had some recent discussion about capturing AC ripple from an alternator. While this can be done with a normal digitial voltmeter set to AC volts, a meter isn't really designed for this. Your standard voltmeter is expecting to see a smooth sine wave pattern, so the choppy spikes from a failed diode may not register properly. That was then. This is now. Select the charging test on the battery analyzer and you'll see this thing is designed to capture AC ripple. This is only part of the charging test, but definitely the best part:





In this picture, my truck's alternator was putting out only 10 millivolts AC, well below the usual limit of 500 millivolts.

For anybody interested in a battery analyzer, I'd say this is money well spent.