Electrical issues C216, system reset/fob problem

[Bodo]

Hi,
I got the first issue with my CL, has anyone had similar problem? It looks like the whole electronic resets itself after few minutes when you lock the car. In the morning I couldn’t open the doors remote stopped working (new batteries and you can see red light on it when you press the button) I have to open manually then when I stick key in the ignition screen looks like it's resetting itself (flash twice) clock is running around and screen is facing towards passangers, windows don’t work properly when you open the doors you have to do them with the button after that they start to working fine. After you start the engine everything is working as it should, but when you turn the engine off you remote is working for few minutes and stops working. Also what is weird is when you turn the engine off and take the key from ignition screen flashes once. I reckon that the secondary battery is gone but did any one have similar problem and can help me? I also know that the car hasn't been used much for last few months and this could have killed the battery. I will be grateful for any suggestions or advice. Thank you

 

[mattkh]

Charge the car batteries.

 

[Blobcat]

As per above, in the first instance I’d get a battery conditioner on it and get the batteries up to charge.

The battery age will be stamped n one of the terminal posts in a 4 digit code - week and year

 

[Bodo]

Both batteries are 3.5 years old, but car stood for last 3-4 months in the garage and I reckon that’s killed battery, start battery seems to be ok, probably the best option is just to replace both to avoid future problems

 

[Bodo]

I have one more question. Can I disconnect the boot battery without any later issues to the car. I want to take it out to put in to the charger. Or should I connect the charger to the battery under the boot as they are linked together? Any thoughts?

 

[alexanderfoti]

Rear battery is flat, as above. You can charge the boot battery from the front fuse box if you want to leave it on.

Disconnect the front one first, then then rear. Reinstall rear one first, then the front. Keep the disconnected positive leads away from the bodywork during transition

 

[Bodo]

Just ordered 2 battery’s, want to resolve problem for long time. Hopefully I will install them on Tuesday, a little bit more expensive that I thought, I went for AGM in the boot

 

[Bodo]

Thanks for help. Battery changed and everything is working how it should.
The boot battery was to small 75ah

 

[Botus]

if you leave it more than 2 weeks without leaving it on charge there will be no long term fix ....they eat currents non stop.... full english, elevenses, 4 course lunch, tea, dinner, supper, a sneaky kebab and a midnight snack

 

[mioba]

I think it was a somewhat unrequired expense to be fair. A night hooked up an conditioning charger would have been my first call, esp for a young battery since they were MB batteries. Never had one fail within 10 years. IMHO if the cars a keeper 5+ years there is. good value in MB batteries.

 

[Bodo]

I think I've done the right thing.
I just bought this car, it was parked for at least 3-4 months maybe longer, batteries have been replaced 3 years ago but since then drove only 3.5k miles so less than 100miles a month. 5mins after switching off the engine most electronics was not working. Battery in the boot was too small- 70Ah instead of 95Ah and that makes a massive difference.
Maybe I should have replaced only rear battery (in a boot) but I wanted to avoid future problems and need to replace both again.

 

[peterws1957]

I think I've done the right thing.
I just bought this car, it was parked for at least 3-4 months maybe longer, batteries have been replaced 3 years ago but since then drove only 3.5k miles so less than 100miles a month. 5mins after switching off the engine most electronics was not working. Battery in the boot was too small- 70Ah instead of 95Ah and that makes a massive difference.
Maybe I should have replaced only rear battery (in a boot) but I wanted to avoid future problems and need to replace both again.

Yep I think you did the right thing as well. These eat batteries as Botus said. Buy a Ctek or two if you're not going to drive the car regularly.