Key fob failure!!

[Stonefish]

Hello,

Had a minor panic tonight as I left work. Rushing to get out of the car park, I pressed the key fob and nowt happened. Curses!! Thought I'd use the key in the fob. Doors unlocked OK and I thought result. But when I opened the door the alarm went off. Curses2! When the alarm finally stopped I decided to try again. Opened the door, alarm goes off again, but when I inserted the key the alarm stopped and I was able to start the car normally and go home.

Turned out the fob battery was flat (after 2 years and 3 months). I'm using the spare until I can get some new batteries.

Strange this is the first time I've heard my alarm go off and also it also reminded me that I changed the alarm delay to 2 seconds.

 

[Locoblade]

Does the key get charged when inserted in the dash?

 

[GeoffDunk]

Key should charge when inserted i dash. Us comfort key guys have to replace batteries. Or is this just a B8.5 setup?

 

[Locoblade]

So you don't have a slot in the dash at all with the comfort key option? Beemers still have the slot IIRC so you just use it occasionally to keep the comfort key charged, seems a better way to do it but probably more expensive not being able to ditch the slot mechanism

 

[GeoffDunk]

Yes, Audi still have the slot the same as the wifes X5, you just never put the key in, it stays nicely tucked away in the fob pocket of a pair of jeans, its a perfect fit.

BMW comfort keys are also NOT rechargable, I have to regulaly replace the 3202 battery, it doesn;t last as long as it would a normal fob as it continually comunicates with the vehicle.

 

[Locoblade]

Ah every day's a school day, my two previous BMWs didnt have comfort access but ISTR reading forum recommendations for people with comfort access to plug it in occasionally to charge it.

Seems odd they wouldn't / couldn't fit a battery that could charge from the slot seeing as the facility is there anyway, if the comfort key battery can last 2 years its not as though it's has especially high power requirements.

 

[GeoffDunk]

Plugging it in occasionally does nothing on a BMW as it has a standard CR3202 battery in it. On the BMW the battery last approx. 12 months, I know because I replace the batteries in both key fobs every year. They use more power than the non comfort access ones because they constantly communicate with the car when in range.

I have just checked my RS 4 key fob and that's the same, CR3202 which will need replacing, no way of charging it either.

Funny enough its never been inserted into the dashboard, not that makes any difference.

Both the Audi and BMW key store the cars service and running history along with error code logs that why the service desk pops them in the little dock when you take you car for a service, it reads all the info including owner details if setup.

 

[Locoblade]

Yup but what I was trying to say is if a CR3202 button battery can last for 12-24 months then the key still has very low power requirements even if it's more than a standard key. There's no reason they couldn't still put a rechargeable version in with an induction loop to charge it from the slot.

 

[Stonefish]

Got new batteries. It seems the battery is just for the remote control. The key fob will work without the battery so that part must be powered by some induction process when in the key slot. I found the physical key can be used to lock the car and I'm pretty sure it includes the dead locks and arms the alarm (red light flashing). It can unlock the doors, but won't turn off the alarm. That will go off until the key fob is put in the slot.

 

[Shogun]

I've just got over the biggest nightmare that cost me around 800 quid to fix and it started the same way as yours did
Hopefully not he same problem mate,
In a nutshell the fob stopped working due to a blown sensor or something in the passenger door which made a knock on effect