Car had completely dead battery. Battery replaced. Now, key fobs stopped working

Igotadose

So, my car battery died completely while we were away for a couple of months. Couldn't be jumped or recharged. Got a new battery, car starts and runs fine.

However, the buttons on the keys have stopped locking and unlocking the doors. There's a red LD that blinks when you press the buttons so I don't think the key batteries have gone bad. Just no response at all. I called the dealer who'd never heard of it, told me to check the fuses. Well, as far as I can tell since the manual says the 'key locks' are on the same fuses as the gauges, the fuse is fine. There are a lot of fuses and circuits however.

There were some videos of dubious quality on Youtube on 'programming your key' that involved rituals of inserting and removing the key, opening and closing doors and so on. I think I correctly tried 2 of them to no avail.

Car is 2011 Toyota Auris 1.33. The keys just have open and close buttons and an alarm button. It's not 'keyless' like newer cars, you have to insert and turn keys to start it up.

Suggestions? The locks work mechanically, turn the key in the driver side door all 5 doors unlock. Just like my 1988 Saab did. Kind of quaint, actually.

Del2005

Buy replacement batteries for your keys. Just because they have enough juice to flash an LED doesn't mean that they have enough juice to broadcast a signal.

Igotadose

One key is fairly new, maybe 4 months. Seems the car battery dying is implicated?

T-Maxx

'Check the fuses' - gotta love the dealers! 😆

joebloggs32

Look up lockdoctor.

They can come and reprogram your keys

bazz26

Did you try the method in this video:

https://www.youtube.com/watch?v=jZa31GbEswU

Igotadose

https://www.boards.ie/discussion/comment/121070203#Comment_121070203

Yes, it was one of the two methods I tried.

MrCostington

I've had to do the reprogramming procedure on two cars, so it is a "thing". While I'm not saying the video above is wrong, did you check your manual for the procedure? And as said above, get a new battery for the key fob just to eliminate that.

Igotadose

https://www.boards.ie/discussion/comment/121070945#Comment_121070945

I tried again just now, and I did get the locks to cycle (more than once though, weirdly) but no change after I held both buttons in for 3 seconds and then pressed lock. Still don't work. I also reached out to Lockdoctor.ie, hopefully will hear from them soon.

MrCostington

I've only done it on a Mercedes and Audi, so can't comment on a Toyota, apart to say I found it a "fussy" procedure!

I'm sure the professionals will have you sorted in no time, good luck!

Igotadose

https://www.boards.ie/discussion/comment/121072637#Comment_121072637

Well, I took the car into the local garage for brakes, and he suggested taking it to the local guy that reprogrammed keys.

I did that, and the fellow had problems with it, in that the key programming 'would not stick.' That is, the car would respond to the key clicks once or twice, then stop. It was working when we drove away, but eventually its failed again and no longer responds.

I'm beginning to suspect a more serious problem due to the battery failure, like maybe the computer is toasted somehow? Anyway, suggestions welcome. I'd say the guy that did the reprogramming was good and knowledgeable but he wasn't exactly working out of a dealership, though was clearly the 'key reprogramming guy' for lots of people.

Oh, nothing wrong with the key batteries, either.

MrCostington

Sorry to hear that didn't work out. While I can't say for sure, I doubt anything is fried, unless the alternator provided over 14V without a battery load, but I believe there are safeguards for that. Someone else will no doubt have better knowledge of car electrics/electronics.

ofcork

I had to get a new battery for my avensis last month and key is working fine,in fact still using original 11 years old key so you may have another issue.

Igotadose

Well, it's been 2 months. Thursday last the keys stopped working again, and after the big storm Sunday (car was last run Saturday,) the battery is completely dead yet again. This time, I put a charger on the battery (battery was replaced in September) and it measured 7.3V.

After a couple of hours, it was up to 9.6V and I called it a night as its gotten too cold and windy and dark to proceed. I will restart the charger tomorrow.

Still, I'm really perplexed as to why the battery drains overnight. It had only sat for a day. Temp got down maybe to 5deg. The lights weren't on. The doors were shut and locked and there was no dome light. No radio turned on. Just plain weird, could the on board computer be fried somehow? I did have the brake system serviced a month ago including replacing a brake sensor that kept reporting brake system failing when it wasn't, but that was fixed and nothing odd seen, until Thursday.

I'm wondering if this car's just telling me it's time for the scrapper. It's just over 100k miles, but in the last year or so it's repair after repair...

Tippbhoy1

https://www.boards.ie/discussion/comment/121364715#Comment_121364715

This reminds me of a problem I had years ago with an A4. It started out with the key fobs and central locking not working. Id have to open the car with the key, start her and 20 minutes of driving later you’d hear a click and the central locking was back working. This went on a while, a matter of months on and off, then the car started losing charge overnight and wouldn’t start. Turned out the unit that ran the central locking (and some other bits, I think called the convenience box) was faulty and draining the battery. Replaced that, reprogrammed keys, never had a problem again.

brendan001

Try narrow down the issue by removing some fuses overnight and see which circuit of the electrics is draining the battery. Might take some days to nail the issue, could be a stuck relay.

Igotadose

https://www.boards.ie/discussion/comment/121364799#Comment_121364799

This is a great suggestion. With the keys not working right, I wonder if that's the circuit that's draining the battery like tippboy pointed out on his Audi.

zg3409

You need proper diagnosis.

If a battery has been let go flat a few times then it's typically knackered and needs replacing anyway. Then you check if it's charging while driving and then if something is draining it overnight.

Without a good 12 volt you may continue to have key problems. Some remote central locking systems use rolling codes and if 12 volt goes flat then they lose synchronisation. But you need a good 12 volt system before you consider the keys. Central locking won't open with a dead battery.