The same thing happened with me 2 years in a row right after the state/emissions inspection. It's strange the dealer or JLR don't seem to know how to roll out a fix, or it's swept under the rug.

Last year I had a completely flat battery day after service. I took in for a battery test, and they said the results were inconclusive. So I bought a new battery because I figured it may have been on its last legs (2016). This year a low battery warning sign came up a couple days later, and my battery is barely used at 9 months. I drove it a while before it conked out. I took it for long drives and got up in the revs but didn't work.

Because I bought my platinum battery from Advance Auto Parts and under warranty, they covered it. Depending on how old your car is, whether or not you have the original battery, and if the issue affects your car: my strategy is to have get a battery at a local place with its warranty, and go there - rather than the dealer - after your service if you have battery related problems.

 

But did you do the battery disconnect trick? That might have saved you a trip to the battery store.
It seems you're only doing the battery reset when you replace the battery, which is too late.

 

Not familiar with how to reset or disconnect the battery - is it fairly straight forward? If it requires a tool kit and 5 years in the trade it's not something I'd want to try and DIY.

Each time I had this OBDII battery drain, I was at the dealer for hours while they ran tests and both times they couldn't pinpoint the cause or whether or not the battery was still good. I'm surprised there isn't some sort of memo that advises a battery reset/disconnect could fix this. From what I gather it's not that rare of an occurence, and who knows what portion of the batteries are still functional or not after this drain.

 

Disconnecting then reconnecting the battery is truly a five minute job.
1. Remove the cover panels over the battery area and floor of the trunk/boot, including the box/cubby.
2. Locate the ground/earth cable which runs from the negative battery terminal to a bolt on the floor of the trunk/boot (thick black cable).
3. Undo and remove that floor hold down nut (12 or 13 mm???) and disconnect the cable, making sure to keep it up in the air away from any contact with metal.
4. Leave the cable disconnected for about a minute (although 20 seconds is probably long enough).
5. Reconnect the cable and bolt the nut back on.
6. Refit the cubby and panels.
Bingo, you have now reset the BMS (Battery Management System)!

 

I dropped my car off at the dealership last thursday and the service manager hooked up a non-jaguar code reader to the OBD2 port. They then disconnected the code reader and parked the car, locked, until this morning when they opened the door and started the car. The dealership experienced no current drain like I did for the past two years following a state emissions inspection. In speaking with the service manager, the only difference between what they did and what happened to me last week was that they couldn't hook up the emissions tester, because the car wasn't ready for another emissions inspection. In any event, the dealership could not duplicate the OBD2 battery drain problem so I guess I will just have to remember to disconnect the negative terminal after state emission inspections.

John

 

Remember to check the light in the hazard switch about 10 minutes after locking. If it's still on, then you need to do the battery reset.

 

It happens with some code readers and not others. My state emissions (MA) causes it. My code reader does not. So maybe they couldn't reproduce it with that specific code reader. But mine happens every single year with state inspection.

 

You don't happen to have anything from Jaguar indicating what is covered under the factory and CPO warranty do you? Mine has the balance of the factory and then 2 years of CPO and the dealer was clueless. Both the one in Atlanta when I bought the car and the one in Pennsylvania where I live.

My CPO paperwork was literally a photocopy of a photocopied form with a few lines filled out by the sales person. They had no official documentation on what was covered and what wasn't, nor did the sales manager or anyone else at either dealership. Unfortunately my dealings with the dealership have shown them to be completely clueless.

 

I asked the service manager for a copy of the CPO warranty because I couldn't find anything on the internet and never got any written warranty when I purchased my car. He told me they don't even have anything in writing and they have to call Jaguar to see if a repair is covered. He originally told me the battery wasn't covered by the CPO warranty and wasn't covered under the new part one year warranty because the battery was replaced less than a year earlier under the original factory warranty. He said that had I paid for the battery, it would have been prorated and I would receive a partial refund. Then he said that the battery would be prorated based on a two year battery life so I should expect to pay 1/2 price for a new battery. When I went to pick up the new battery, there was no charge. Since my CPO is up at the end of August I am less concerned about what is covered than I would have been a year ago.

John

 

Just to repeat what everyone has said; after any service or check (when OBDII port may have been connected) look at the hazard warning triangle after locking your car. It will initially be lit red. If it is still on after 15 minutes, you need to do the disconnect/reconnect on the battery to reset it, otherwise you'll have a dead battery after about 2 days. Always happens to my 2015 (2016 model) V6S despite what dealers may say. Dead simple to do as explained above, but have your keys ready when you re-connect - my alarm ALWAYS goes off, so a press of the unlock button is needed to stop it.