wajeeh

i have also dead aux battery should i replace it

jimbo1763

I am not sure I understand what you are asking.

I assume you have the SBC braking system, since you have an auxiliary battery. If your aux battery is dead, you may get all sorts of strange effects and messages from that, so yes, replace the aux battery. You may find that doing so takes care of the error messages.

The aux battery is meant to be a backup power supply to the SBC brakes in the event such is needed.

Maroc_Specops

no leave it. what a sucker.

bbirdwell

Please place in your profile your car (i.e. 2004 E500 4Matic) or some such description. Listing your location also assists due to different model variations (Japan, Europe, North America, etc).

If auxiliary battery is dead, replace it now! Assuming you have SBC, in the event of the main electrical system, that little tiny auxiliary battery is all that is powering your "brake-by-wire" computer-controlled brake system. You literally have minutes before you essentially have no brakes!

Replace auxiliary battery, confirm relay K57-2 is functioning to ensure it charges.