unlocking problem W220

[Johig]

Since the cold weather started (it may be unrelated, of course) the keyless go card and one of the conventional keys I have have stopped working first thing in the morning. Neither will open the car. The other conventional key works fine and once the car is opened with that, the other two keys work fine. During the day and coming home in the evening they all work fine. I've tried new batteries but the problem remains. I can't think of anything at home in the morning that could be causing any sort of interference. There is a WAP for the home computer network but it's inside the house and 25 ft away (and on all the time, not just in the morning). Does anyone have any ideas what the problem is.

 

[Johig]

Solved perhaps

Since writing the post I've had the same problem off and on. Today the car wouldn't open. I opened the door with the key thingy in the electronic key and the alarm went off. I shut the door and relocked it (with the key thingy) and went into the house while the alarm/hazards ran for a while and then shut off. Then tried again and the car opened from inside the house 20ft away using the normal key. The one thing that was different was that because I hadn't gone outside the house the two 500W security lights weren't on. It could just be coincidence of course. What do people think, could two fairly powerful lights affect the key/keyless go operation?

 

[LTD]

Back to basics.

Fit new batteries and see if that helps

 

[Johig]

Thanks for troubling to reply but I said in the original post that I'd changed the batteries. I meant the key batteries. I haven't checked the car battery. I wonder if it being at a low charge/on the way out could cause this.

 

[Gemdo]

Best person i think to ask is Olly 'BlackC55' he was a demon at helping me resolve a similar problem but mine was the ignition switch. Check my post 'W203 C240 doesn't start please help' Its not like you can't get in full stop like mine its temperamental. But things are suggested like disconnect your car battery for an hour and then reconnect and test. But BlackC55 is on the post so you could private message him directly to see a potential solution?

Good luck with it pal and keep us updated

 

[biturbo]

mines been playing up, the keyless go that is since the cold weather.
I can get in if i try and open the rear doors instead.
Try it.

 

[Johig]

I think the problem may have been the car battery which was a bit low at 12.48V. Given the -1 to -2 temperature, the capacity was probably not much above 50-60%. I wonder if fairly short journeys of 13 miles each way, night and morning with the lights, heater, radio etc etc on have gradually sapped the battery and given how many electrical wonders the car has, perhaps it needs a fairly high state of charge to work properly. Its had a day on trickle charge and seems to work fine (after the key was resynch'd) so I'll keep an eye on it and report back. If anyone else is having this kind of wierd problem I'd suggest checking the SoC of the car battery.

 

[BlackC55]

Check the date stamp on the battery. 5 years plus is normally enough.