SL/R230: Key Not Recognized + Consumer Electronics Offline
I only drive my 2004 SL500 about once a week, and when I do, it's usually just to somewhere like the local grocery store. Every time I drive, the consumer electronics are offline (I get the error message in my display), but they come back on after a few minutes. This has been happening for quite a while, pretty much ever since I stopped driving it every day. So this may be normal, but I'm wondering if it's an indicator of other problems?
For about the last month, my keyless go has no longer worked. I have to stick the fob into the ignition in order to drive. When I try to hit the Start button without the fob in the ignition, I get the "Key not recognized" error message. I've tried it with the fob in many different locations, inside and outside of my purse, in my hand, etc. But I can still lock the car by touching the handle button, or unlock it by touching the handle... usually. It's fairly consistent that I can unlock/lock it normally on the driver side door, but I haven't had much luck with the passenger door or trunk.
I only have one smart key which was newly replaced about 2.5 years ago. I used a battery tester to see that the battery is still good.
Before I go to a dealership, I'm wondering if you have any ideas of what should be checked? From what I gather, I possibly need to:
- Change the battery in my smart key (even though it tested good)
- Change my secondary/consumer electronics battery
- Check the main/starter battery because the consumer battery will auto-disable itself if the main battery is weak
- Check the alternator or other electrical system?
Any other ideas? I don't know anything about car mechanics, so let me know if I'm off.
Thanks!
I only drive my 2004 SL500 about once a week, and when I do, it's usually just to somewhere like the local grocery store. Every time I drive, the consumer electronics are offline (I get the error message in my display), but they come back on after a few minutes. This has been happening for quite a while, pretty much ever since I stopped driving it every day. So this may be normal, but I'm wondering if it's an indicator of other problems?
For about the last month, my keyless go has no longer worked. I have to stick the fob into the ignition in order to drive. When I try to hit the Start button without the fob in the ignition, I get the "Key not recognized" error message. I've tried it with the fob in many different locations, inside and outside of my purse, in my hand, etc. But I can still lock the car by touching the handle button, or unlock it by touching the handle... usually. It's fairly consistent that I can unlock/lock it normally on the driver side door, but I haven't had much luck with the passenger door or trunk.
I only have one smart key which was newly replaced about 2.5 years ago. I used a battery tester to see that the battery is still good.
Before I go to a dealership, I'm wondering if you have any ideas of what should be checked? From what I gather, I possibly need to:
- Change the battery in my smart key (even though it tested good)
- Change my secondary/consumer electronics battery
- Check the main/starter battery because the consumer battery will auto-disable itself if the main battery is weak
- Check the alternator or other electrical system?
Thanks!


Last edited by Benz-O-Rama; Jan 22, 2011 at 10:45 PM.
Last year the car could sit 2 weeks without the message or symptoms. This winter, that window had reduced itself to about 5 days. I had my indie replace the rear battery, no message or symptoms since. Better to have a shop with Star do the swap as disconnecting the battery will cause several codes that should be cleared.
The net is that rear batteries in the 2004 - 2006 cars are nearing end of life, depending on climate, how the car has been used, etc. I'm sure these cars never did this so frequently when new.
The OEM MB rear battery runs about $200, and add a little for install, money well spent IMO.
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Part number for the MB hard wired tender? I need one if it isn't way more than a CTEK.
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Last edited by AMG903L; Oct 30, 2012 at 10:19 PM.
Mine could sit no more than 5 days and it would be dead. Problem solved for 40 bucks.
Rear Main = B10049
Front Backup = B14115

I reckon the sl 600 have the same standard battery?
Maybe the E55 is different, or it has been upgraded by another owner?




