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Do I need to make sure the car is in Sleep mode before swapping the main battery- and would it even go into Sleep mode with the boot/trunk open? I just want to make sure I don't fry the electronics. I've changed other car batteries before so I know how to actually remove and install a battery but as the SL has fairly complex electronics I don't want to mess them up. Thanks for any advice on this.
Not absolutely necessary but it can't hurt. Open the trunk and take the key away from the car. It should enter sleep mode in 10 minutes or so. When you go back to the car don't take the key with you. Loosen the negative terminal nut and then quickly pull it. I've found it to be unnecessary to have a backup battery to hold settings. It may reset learning for your driving, but sometimes that's a good thing.
While the battery is disconnected you have the opportunity to do a simple test of the auxiliary battery system. Take a voltage measurement from the positive battery cable to body ground. It should read less than 0.5 V, assuming you did not connect a backup battery. If it reads more than that then there's a problem with your auxiliary battery system.
The other matter I think is important is to be deliberate when you're making the final connection with the new battery. I hook up the positive terminal first. Then quickly install and seat the negative terminal to minimize sparks. The negative terminal on the SL includes the battery sense module. Make sure the single LIN bus wire is connected to that terminal.
On the R231 I'm not aware of any diagnostic function to tell the system a new battery was installed. It figures it out on its own.
'13 SL550 Mars Red, Designo White interior, B and O sound
As others have said: nothing needs to be done beyond normal caution. I recently replaced my consumables battery (the big one in the boot/trunk) and it took all of ten minutes. I noted nothing changed or lost EXCEPT the A and B odometers did reset to zero.
(I also recently replaced the starter battery behind the right-hand seat with the same ease and no issues afterwards.)
I did notice the transmission change map but, again, as stated earlier, that's not necessarily a bad thing.
As others have said: nothing needs to be done beyond normal caution. I recently replaced my consumables battery (the big one in the boot/trunk) and it took all of ten minutes. I noted nothing changed or lost EXCEPT the A and B odometers did reset to zero.
(I also recently replaced the starter battery behind the right-hand seat with the same ease and no issues afterwards.)
I did notice the transmission change map but, again, as stated earlier, that's not necessarily a bad thing.
The transmission behaviour change is normal and it quickly adapted back after a couple of minutes of driving. I have that same behaviour in all MB models I own, the transmission shift is different after unplugging the battery and plugging back in.
Thanks, thats really helpful. I've got Keyless Go so is there anything extra I'd need to do besides keeping the key away from the vehicle? And should the doors be locked?
Thanks, thats really helpful. I've got Keyless Go so is there anything extra I'd need to do besides keeping the key away from the vehicle? And should the doors be locked?
not sure if you are asking me but it is fine to have the vehicle unlocked and the vehicle alarm system disarmed for the unplug procedure.
Thanks, thats really helpful. I've got Keyless Go so is there anything extra I'd need to do besides keeping the key away from the vehicle? And should the doors be locked?
You can leave the vehicle unlocked. Be careful not to close the trunk with the battery disconnected.
You can leave the vehicle unlocked. Be careful not to close the trunk with the battery disconnected.
ah that got me curious, I always wondered if say: doors are locked, keys are in the car, battery is unplugged and hood is closed, how will anyone ever release the latch and pop the hood if that happens?
ah that got me curious, I always wondered if say: doors are locked, keys are in the car, battery is unplugged and hood is closed, how will anyone ever release the latch and pop the hood if that happens?
All sorted now. The only thing I had to reset were the auto power folding mirrors - by folding them in and out a couple of times with the door buttons. As they were still set up to fold automatically according to the vehicle display but weren't moving.
Definitely worth puttng a towel over the edge of the boot/trunk in case it decides to close (and to protect the paintwork), and to leave the drivers door unlocked and not quite shut.
My scanner told me the car didn't have the option to register the new battery - Mine's an early one - is this common to all R231s as I've seen comments saying even with Xentry they didn't have the option to code the new battery.
All sorted now. ...
My scanner told me the car didn't have the option to register the new battery - Mine's an early one - is this common to all R231s as I've seen comments saying even with Xentry they didn't have the option to code the new battery.
Correct. There's no function for battery reset on the R231.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
