So recently got an XF and the Battery Warning Light stays on while driving. What does this mean ? Does the car need a new battery ? Has close to 80k I believe it still have the original battery. Please help. Thanks

 

Looks like you need a new battery. Or an alternator. Or both..I would go with both. Did this happen before you bought the car?

 

Ditto

 

I'd start with checking the cars running voltage which should be over 12.3 volts when idling. If that's good and the batteries connections are good I'd get the battery checked. If you're battery has never been dead since the battery symbol been on, its probably your battery as running with no alt charge will drain a battery.

 

Changed the battery to a brand new one but the battery warning light still remains on. Does the light have to be cleared ? Please help thanks.

 

I think when a new battery goes in the charging system has to re-calibrate which is by driving the car with the normal loads you would put on the system.

You don't say what sort of driving you do. If the previous owner used to do a lot of ks and long drives and you do short drives the system would have metered the alternator to suit the loads he put on it, but if it's now doing short hops the system may not have learnt yet and is not charging your battery sufficiently.

I'd say take the car for a good thrash in the countryside.

 

I just got this car and I drive maybe about 30 miles daily. I went to have the battery that was in there tested and they said the battery needs recharging and needs to be replaced. So they replaced the battery with a brand new one. However the Battery Warning Light is still on. I drove about 26 miles today after the new battery was installed but warning light is still on. Do you think its the alternator ? Or does the battery warning message must be cleared ? I would like to get this resolved asap. Thanks for all your help

 

The car has a Battery Monitoring System which controls the alternator feed to the battery. Apparently when a new battery goes in this cannot relearn the new battery info itself and has to be reset, so a trip to the dealer may be in order.- try ringing a dealer and speak to the service manager to confirm this.

Check the wiring to the battery first- there is a thin wire to the monitoring system and if this is broken or worn it can cause the light.

 

This is from the workshop manual

"If a new battery is fitted to the vehicle, the battery monitoring system module will require re-calibrating using the Jaguar
approved diagnostic system.".

However, it also seems like it re-calibrates itself sometimes... page 2506:

"Periodically the battery monitoring system module will instigate a self-calibration routine. To self calibrate, the battery
monitoring system first charges the battery to its full condition.
• NOTE: If the vehicle is only driven for short periods the charging process could take a number of days to complete.
Once the battery is fully charged, the battery monitoring system will discharge the battery to approximately 75% of its full
state of charge, but never lower than 12.2 V. The time taken to complete this part of the routine is dependent on the
electrical load on the vehicle.
When the second part of the routine has been successfully completed, the battery monitoring system will return the
battery to its optimum level of charge. The optimum level of charge will be between 12.6 V and 15 V, depending on
battery condition, temperature and loading."

There's also a further detailed description of what the monitoring system does on page 2507.

So you can either just go and get the BMS reset (I'd enquire about the cost first) or just keep driving it and hopefully it will reset itself.

 

So in other words the light will eventually clear off upon driving ?

 

It should. Not knowing how often the self calibrating thing kicks in, it's hard to say how long it will take, but I'd imagine doing 30 miles a day it shouldn't take too long.
Or just take it for a long drive.
As long as the alternator is OK(and there doesn't seem to be anything much to indicate that it's not because if it wasn't charging you would have stopped long ago) there shouldn't be anything to worry about.

 

Lol...yes...and you can also put on one of those transformer decals on you car and pretend that it will turn into bumblebee.

This really could be a simple problem, but most of the time these things have a cause that is not so simple. I don't know if you have been charging your battery. If the alternator is out, then your battery won't last more than two or three days if you are driving 30 miles per day. You can easily go to any autozone type store and they can check the voltage from your alternator. That would tell you if you have a charging problem. I definitely would not pack a picnic and put the blonde in the car for a nice countryside jaunt where you might end up stranded in the middle of nowhere. Good luck

 

Especially if the wife finds out.

It would be simple enough to measure system voltage at the battery with a volt ohm meter. Measure with the engine off, at idle and at 2K RPM or so.

 

Well yeah. I sort of assumed that whoever tested the battery and put the new one in had tested across the terminals with the engine running to make sure it was charging.
It's pretty standard practice you would hope when the guy has the multimeter right there to test.

You can do it yourself of course with a cheap multimeter (probably under ten quid).
Just do the above test and if it's reading over the 12.3 volts ring the blonde.

 

You need a new alternator.

 

I had the battery light on the dash for about a week until, yes, catastrophic electrical failure. All systems stopped, no lights no heat no gears. AA rescued me, got to a garage who replaced the alternator & bms. They charged the battery and put it back on. It held its charge after testing and running the car. Still the battery warning light remained. New battery, still there. Tried clearing all codes. Still there. Went to a software specialist, couldn't get rid of it. I have had the car back for 2 months, regularly driving 60 miles a day. Still there. It hasn't recalibrate. I monitor the charge in car with a simple USB charger. The battery is constantly at 13.5 to 14 v.
trouble is I can't use the windscreen heater to defrost, nor the rear screen, no heated seats, no heated wing mirrors etc etc due to high power requirements.
Can anyone suggest anything? Next port of call is dealership but don't really want to!
TIA

 

Sounds like an inappropriate alternator. Provides charge (apparently) but does not cooperate with the signalling as it should.

 

Hi,

I had exactly the same problem, battery/alternator light came on and would not go away.

Replaced battery, alternator & drive belt, but light still stayed on. Replaced battery monitor cable, still light wouldn't go away. Got the SSD software and cable, performed battery reset procedure. Still the light would not go away...

Battery was been charged at around 13.8 but after 6 months of living with red light (always came on after about 30 seconds) I noticed battery wasn't holding its charge, dropping to 12.2. Heated and cooled seats, window defrost and other electrics did not work properly and windows were slow to wind up.

Then it broke down due to low battery problems, just cut out and would not start, got a recovery truck to boost start it was OK again.

Took the car in for a gearbox service at local Jag independent specialist, who found the problem while car was with him....water ingress to rear junction box which had damaged the unit, corroded pins and corroded cables.

He replaced this with a second-hand junction box, repaired the damaged cables and works perfect now.

I believe the junction box needs to be a close match, and requires reprogramming with Jaguar software.

Maybe yours has the same issue.

T

 

I've a similar problem...changed battery ....was ok for about a mile and the battery warning light came on again............How far can you drive with this light on? As everything started shutting down on the old battery ..........Any help appreciated

 

Have you checked if the alternator is charging battery, it should read above 13.5 volts when engine is running and charging battery.
It should start charging battery after a few minutes after turning engine on.

Use a voltmeter or a plug in tester into cigarette socket.

If alternator and battery are OK, it could be faulty/damaged Battery Monitoring System cable. (cable that is on the earth on battery and connects to earth point on car)

Highly unlikely that you need the Battery Reset Procedure from a dealer. I have replaced the battery several times and only had to reset clock, handbrake.

It could also be a problem with the rear junction box, located behind trim in boot/trunk next to battery.

Pull back trim and check for any damaged/rusty wires, water/moisture can get in there and cause corrosion.