Any help appreciated. I have a 2009 XF with the 4.2 NA. I have 2 smart key fobs. A few days ago, after driving away from the house, I got a "smart key low battery" message on the dash. Turned around and went home because I didn't want to take a chance on no restart. I put brand new battery in that fob and tried again. Starts up fine but again after idling a minute or so, got the smart key low battery message again. So, went in the house and put that fob far out of range and tried the other fob...same result. So I put a brand new battery in that fob and tried again. Still getting the "smart key low battery" message with either fob and both with fresh batteries. What is going on here? I'm scared to death because a few years ago I changed the car battery myself as I have done my whole life, and lost the computer communication. After towing to a dealer, I spent $5000 (yes, $5000) because they said that by disconnecting the battery and installing a new one myself, I blew up the main brain, fobs, instrument cluster..... Since then, I have actually paid a dealer to change this car's 12v battery because I am terrified of the car. Oh and btw, the dealer was unable to reprogram the docking port for the fob even after consultation with the factory and so I took the car back with no docking port. If I dare insert a fob into the docking port, it locks on and will not give it back and it has no communication anyway.

What's up with my smart key low battery message with brand new batteries?

 

I’ve read many times that you should only use the Duracell CR3032 as a replacement battery for the fob.

I’m surprised you had such an expensive fix when you changed the main battery as it’s a pre facelift and you don’t need to follow the battery replacement time protocol that the later models require.

i changed my main battery a few months back and the car had no power for the few minutes that I moved the old battery out and new one in and I had no problems whatsoever.

My docking port also doesn’t like to give up the key fob with one of my fobs but I use a pair of needle nose pliers to gently grab onto the fob and remove it.

 

Thanks for feedback. The fob batteries I use are Duracell cr 3032 lithium. I don't know about facelift you mention, but the dealer told me that changing the main battery is not a diy job unless you have a "life support" computer to connect to the battery somehow before removing terminals. Too bad Jaguar doesn't tell you that in the owner manual. I'm hoping that right now, I am not experiencing some sort of "pre-disaster" symptom with the fob smart key low battery warning. It's a dilemma. The car at this point is only worth about $4000-$5000, has the awful rippled leather dash that was a known factory adhesive problem and black paint job is overdue.

 

I'm sure you've started the car a few times since you replaced the batteries so it's not a "learning process" issue.
Only other thing I can think of is that even the CR3032 Duracells from EbAy and Amazon are less than ideal.
I pay a couple of $$$ more and get mine from Home Depot/Ace/Lowes etc....
Also, try not to get any finger oils on the batteries when changing them out.

 

I'll take your advice on new batteries from Home Depot or other. Yes I did buy the "new" batteries from amazon. Yes, I have , and am able to start the car without any issues and the "smart key low battery" does not immediately appear. It seems to come on with either fob after a minute or so of starting the car.

 

The dealer has given you the wrong information about battery disconnects, there is no problem with the early pre-facelift cars. You can disconnect the battery with no fear of losing the locking, this only applies to the later facelift cars.

 

I just called the Jaguar Dealer service manager and he told me that the car must be connected to life support before disconnecting battery.
On another note, I replaced the fob batteries with store bought new ones and at the moment I do not have the smart key low battery message.

Diffferent subject, does anyone have a downloadable wiring diagram for the 2009 XF 4.2? And.....where exactly is the secondary air solenoid and what does it look like? I'm getting a secondary air injection low flow and low flow bank one obd fault. The air injection pump IS running at start up.

 

Does this file help?

 

thank you very much . That will be helpful.