Actually that doesn't seem bizarre to me at all. Ever since my first "module-ised" Jaguar (an XJ40, years ago) I've got into the habit of load-shedding as I get to the end of a trip, and always driving straight after any battery draining activity. For example, I always take the car for a drive right after washing and detailing it, because I know I've drained the battery. Both my XJ40s, my S-Type, my X308 and my X350 were all capable of going from cranking fine to the infamous 'click' seemingly at the drop of a hat.

 

Continuing to knock on wood. 10 days since I haven’t run the kitty in accessory mode, and she’s always started, Not setting alarm overnight night in garage. Driving at least every other day, and not using battery maintainer. Still using using the standard start procedure: fob in pocket, open garage door, open driver door,get in, put on seat belt, close driver door, press brake pedal, press start button, and she fires right up. Put top down. Wait until revs drop to normal idle, back out & rumble away.

I guess the real test now would be to run her in accessory mode for a while. Turn her off. And try to start the next morning. If the failure is not reproducible then she’s got some other demon.b

 

Another update…haven’t tried to leave the kitty overnite without starting it after running in accessory mode only. And I’ve yet to have a repeat of the starting issue.

 

Just FYI in both my XK’s a 12 XKR and a 13 XKR-S I get these codes for body control module, infotainment center A, even the cluster….

 

Well damn! Had a friend hook up a Obd tool to reset the TPMS codes, which is another story, and after running it on accessory for that…the kitty was up to her old tricks. It’s definitely not a low voltage issues, as the battery was recently load tested, and I get 12.5 volts at the engine fuse block.

Had to do the battery disconnect reset dance to get the kitty to purr again.

 

Hate to be repetitive but this is the battery being run down after having the car in accessory mode for an extended period. 12.5 volts is barely enough.

ps: why does your signature say your car is lunar grey?

 

12.5 volts is too low which explains your problems, either the battery’s the problem or something’s draining it.

EDIT: measure current draw with car turned on but engine not running, that’ll tell you if there’s too much load on the battery.

 

As mentioned above sometimes pushing harder on the brake pedal works. But what you want to monitor are the brake lights.
Do they come on when stepping on the brake pedal and the car is not starting?
Just another thing to check.
.
.
.

 

So, I posted this question on the Facebook “Jaguar XK8/XKR” page. And several people are having a similar issue, and their kittys seem to only get it to start after the battery reset dance. But, a few people made suggestions, that I tried as follows: (most agreed the brain or immobilizer gLes wonkers under conditions they have not sorted out, but most agreed this process seems to keep the kitty’s head on straight:

- set security after last use
- unlock to disarm security
- fob in range
- get in car
- close door
- press start button to turn on accessory mode.
- wait until everything comes up…a few seconds
- press brake pedal, then press start button
VROOM!

 

XKDreams,
You measured 12.5volts at a point in time, then assume that battery condition is fine after using Accessory mode for an indeterminate period.
Critical information #1 for system analysis is real-time voltage.
Please use a voltmeter similar to the attached and let us know what you find:




Typical inexpensive voltmeter from online vendor.



Without real-time data, we are all just guessing.

Best regards,
Bill

 

My update. Unless my kitty has sat without running for more than 3 days, I dint put her on a battery maintainer. I just checked her voltage after 3 days, and it’s 12.4 volts, and she started right up. So, I’m convinced it’s not a battery problem, but that somehow her brains get scrambled.

as long as I follow the following, I haven’t had the issue:
- don’t use accessory mode (pressing start without pressing brake to start her) without starting her
- to start her, first press start button without pressing brake, and let everything come up..
- thrn press brake, and then press start…
- vroom..she always starts.

 

12.4 v... do see: https://batteryworld.varta-automotiv...ttery-test-car

My car continues to sit for weeks on end, without issue. No maintainer. But I only get about 3-4 years out of a battery. If it can only hold a charge of ~60% of capacity == a 12.4v reading, I'm replacing it. The time mucking about, the aggravation of systems not working properly, and the embarrassment of requiring a boost while out and about are more expensive than the mere ~$250 for a battery... yes, from the dealer.

Of course, there is no magic. If the quiescent drain exceeds these values, you've got a problem.

XK (X150) - From 2006MY
< 20 min shutdown (after lock/arm condition) < 30mA
33 min shutdown (unlocked) < 30mA
Cheers!

 

I know you’ve got your start sequence, and you’re happy with it, but you’ll get the same satisfying start with the following, and it’s simpler:

- to start her, first press and hold the start button without pressing brake, and let everything come up..
- then press brake…
- vroom..she always starts

 

Here's my post from 2013. It's how I've always started my XKR, notwithstanding the Owner's Handbook to the contrary.



https://www.jaguarforums.com/forum/x...t-start-99436/

 

And we are thankful for it, it was great advice! Use it every time (except in my Lexus, it poo-poos that method).

 

Everything said in this thread points to a bad battery. Proper voltage should 12.8v, not 12.5v. That's your problem right there. Attach a proper trickle charger and fully charge the battery. Or, get a new one for ~200 with a discount. Battery tests at major chain stores do not mean much. I've had a few bad batteries returning good results.

 

Okay, but NEVER NEVER EVER say "trickle charger". Those burn batteries dry. You meant "Battery Maintainer". Big difference, there.

 

Battery Terminology Matters! There's are big differences between (1) a trickle charger, (2) a battery maintainer, and (3) a battery charger.

A trickle charger is dumb. It continually applies a small charge to the battery, and once the battery is fully charged it will keep charging it at the same, constant rate of charge. That can overcharge and damage a flooded (a.k.a. "wet cell") battery by boiling out the electrolyte.

A battery maintainer is smart. It incorporates circuitry that monitors the battery's state of charge and automatically applies varying levels of charge to keep the battery fully charged without overcharging it. Many people call it a "Battery Tender", but that is the brand name of a battery maintainer that I don't recommend. Read my Amazon review of the Battery Tender Jr. that I bought for my XKR:
I recommend the CTEK brand of battery maintainers. They have several models with varying features, and I am very pleased with the CTEK MUS4.3 that I have been using on my XJ because its Recondition Mode worked to resurrect my Stop-Start auxiliary battery. I've also been using a CTEK MUS4.3 on my XKR after I replaced the flooded battery with an Interstate AGM battery from Costco. There are many other quality maintainers on the market, but Jaguar sells the CTEK 3300 as an accessory with its Leaper Logo. You can buy it for less on Amazon without the Jaguar logo.

If your battery is dead, you'll need a Battery Charger with an output of at least 10 amperes to recharge it. Battery maintainers and trickle chargers simply don't have enough output oomph (amperage) to charge a dead battery in a short time.

Weather extremes - Florida summers and Alaska winters - wreak havoc on battery longevity. And once a battery goes dead, it's doomed even though you may have been able to recharge it.

Battery type also matters, but that discussion is for another thread.

 

^^^ Well stated.

 

same issue here, 2013 XKR, new battery installed, car lives with a CTEK permanently attached whilst not driving. I have had identical no crank issues to the lead post. After clearing all DTC's the ones that return almost immediately are as follows:

B1A56-13 Permanent Antenna circuit. Its telling me to check for open circuit. I am also getting U200D-14 Control Module output power A, again its telling me to look for an open circuit.

If i ignore it, i eventually get an engine warning light although i don't know whats causing that, on 2 occasions it caused the car to get into a "no crank" situation where the can-bus appears to stop communications to many parts of the car and a hard reset is required. After hard reset, all is fine for a hundred miles or so then engine warning light.......multiple DTC's return. Rinse, repeat.

Anyone repaired or replaced an antenna?.