I use an elm327 with the Torque app (android) connected through bluetooth, works perfectly and never had any electrical or battery problems.
Just make sure you get a decent quality elm327 and not one of the cheap Chinese knock-offs.
I bought mine a few years ago so sorry I can't link to that one for you.

Thanks man that helped a lot.

wow, that's important to know! I was looking for info on which OBD tool to buy for my XJ L, or whether I should take it to Auto Zone or something similar to ask for a check of the codes. Guess that's not going to happen!

Is it this one?

https://www.amazon.com/Scanner-Bluetooth-OBDATOR-Diagnostic-Android/dp/B074DWH8JR/ref=mp_s_a_1_1_sspa?crid=1P4AGDLBL2636&keywords=el m327+obd2+bluetooth&qid=1550582747&s=gateway&spref ix=elm+327&sr=8-1-spons&psc=1&smid=AH3WM46J9THPR

That is probably the one although your link doesn't work (must be something wrong/missing in that URL).
Maybe this one: Edit - your link works in my post, and maybe yours is a better version than the one I linked to.

I use the OBDLink MX+ BT adapter as is specifically powers down after 2 hours. Plus it's 3 times as fast as next fastest adapter.
I plan to leave it installed in the car from now on. It's a bit expensive at around $100. So far it works good and the car is still doing the start/stop thing. I found this is a great indicator of battery charge. If not stop/starting then the battery is not topped up.

But I just saw it on sale here for $80!!
OBDLink MX+
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.
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My i930 icarsoft can't read the engine module on my 2004 XJ8.
All sorts of engine module info on the 2007 XJ8 VDP,
Unable to upgrade, and no answers to my E Mails, W T F.
Really like the reader, except this one glitch it works great.
Anyone know of a reader able to read the 04 engine module ???????????????

You might want to check on the XJ8 subforum.

Same. That said, after the several weeks it took them to figure it out, now I can OBD.

What was the resolution?

Yes, the Blue Driver. Works flawlessly with Jaguars.

No fancy phone for the Blue Driver.
I'm looking to have access to the engine module on the 04.
The i930 other than that one flaw, is a great reader.

That it's only a problem after the first hookup. I don't know if that is true, but it was true for me.

I use the cheap little Foxwell NT201. It works fine for me. My BT and TorquePro reader immobilized the car on the next drive, but it works fine now too.

So, you are suggesting that an OBD device can be safely plugged in by immediately rebooting the battery management module (momentarily disconnecting battery) after the plug-in?

Not exactly. My car immobilized on the drive after I plugged in my BT OBD2 module. I left it plugged in to work with TorquePro. After leaving it with the dealer for a couple of weeks while they figured out how to clear the problem, they said some cars crap out the first time a customer (they probably said cheap) OBD2 reader is attached. I don't know what they did to clear it, but they called a few times to explain they were struggling to figure it out and fix it. After they gave the car back it has been fine. I thought it might have kept the car alive, maybe creating voltage issues during the next drive. But whatever the cause, it's been fine since just like they said it would.

I have used both an iCarsoft i930 and (now) an iCarsoft LR v2.0 dozens of times as I like to check and clear codes once a fortnight or so and I have never had a battery problem.

That’s good to know😉because I bought the iCarsoft LR 2.0 based on your recommendation last week.👍🏻

That's great, agreed they make a really nice piece of equipment, but back to the original issue.
So far it appears no one makes a reader able to get ANY information from my 04 engine module W T F.:icon_saywhat:
Main reason i posted over here, is so far no luck on the 03-09 section of this site.:icon_hunter:
Looks like the dealer level type of scanner programmer, is what it's going to take.
Any suggestions???

I recently bought " Autel Maxidas DS808 Diagnostic Tool OBD2 Scanner:" . It has great battery backup, a lot of features and the tech support is also amazing. It's a great product. You Should read more about OBD2 scanner here before purchasing so that the product suites your needs.