I have a 2015 XK with about 65,000 miles. It normally starts right up. About five percent of the time it hesitates a bit but starts. About once a week it will not start at all. Interior lights up so the car recognizes the key. And when I put my key in the key slot it still doesn't start. I leave it alone for five minutes or so and then it normally starts up like nothing was wrong. If has thrown a gear box error code when it hesitated to start. Any ideas what this could be? BTW, I replaced the car battery about two years ago and did not use a glass matt battery. The battery tests fine but it has always given me a bit of trouble (sound system going to FM on restart rather than staying on sattlelite...) Any thoughts?

 

How has the battery given you "a bit of trouble"?

 

Lead acid battery is standard for our cars, Glass Mat is not an issue assuming it was sized correctly. Voltage and amperage can be an issue. You mention it tests fine. Many say that and the common response is, what is the resting voltage at the battery before starting the engine? Have you had it load tested? Auto parts stores will do it at no cost. What is the resting voltage? Please let us know. Best place to start analyzing is power source.

 

Every now and then I get a message saying that the battery is low. Sometimes the audio doesn't remember that it was on Sat and switches to FM. I take it to an autoparts store and they test it and says its fine. I had the same issue on my previous XK where the battery tested find at auto parts store. When I replaced it all those trouble went away. It also tells me constantly that I need to replace my keyfob battery even after replacing it with a quality duracell the day before. Not sure if ttat is related.

 

Tom, are you using a battery maintainer when not using the car such as a Ctek?

 

There’s your answer.

 

I drive it every days, so no.

 

One of the modules may be drawing excess current when the car is shut down. I've never used a maintainer even though I have one. I checked the current draw when shut down - it was around 6 milliamps which is negligible. It might be worth checking that.

 

You think it is a bad car battery?

 

It's possible.