SL 500 Flat Battery Problem

[chris5]

Ive got a 2003 SL 500 and after 1-2 days the battery goes flat and I have the warning "consumer electrics offline ", Ive had it into a Ind Merc Dealer who says its the ECU and it will cost around £800 to replace, anybody else had this fault, obviously somthing somewhere must be draining power,
Thanks Chris

[5 wh]

We had this in our SL500 recently.The car has 2 batteries and the one in the boot was past its best.After we replaced it there were no more problems.
You should replace both batteries with new ones before investigating the ECU.

[markbe]

5 wh said:

We had this in our SL500 recently.The car has 2 batteries and the one in the boot was past its best.After we replaced it there were no more problems.
You should replace both batteries with new ones before investigating the ECU.

Totally agree, there nothing wrong with the ECU, it is just the battery in the boot low on charge. First put it on charge for 48 hours having disconnected the negative terminal [10mm spanner]. When charged check
everything is switched off when you take the key out of the ignition.
Worst scenario is you will need a new boot battery.
Lastly find another garage that knows about current Mercs.

Mark.

[chris5]

Thanks chaps, I thought they may on the make, spoke to another chap who said the boot battery needs to have certain loading capacity, which i'm not sure mine is, I will check this first.You confirmed what I thought.