Member
This question is for the 2018 540i NOT the E36.
I need to figure out what is draining my battery and failing to start even with the new battery booster I just purchased. What are the non essential fuses i can pull before attempting to jump start the car? Because just attempting to jump it seems to drain the jump booster I just bought. As soon as I click the ignition everything goes dead.
Also is it ok to jump the car directly from the battery and NOT from under the hood?
Member
Originally Posted by innerbimmer
NO!!!! Use the under-hood terminals!
Member
I'll need someone to explain just how the car "knows" that the power is coming from somewhere it's not supposed to.... as far as I can see, power from the battery terminals (standalone or augmented by a jumper) has to look the same the the electronics.
Also "the new booster I just bought" almost certainly didn't come with a charge... you have to charge the booster so that it can provide amps to the car. There is also the (admittedly low) possibility that the booster is defective.
Last edited by Honolulu; 05-30-2022 at 03:43 PM.
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
Member
If your BMW has an IBS (intelligent battery sensor)…AND…it is still connected to the car when you attempt to jump or charge it…then it does know where you have attached jumper cables (kind of). It may not know WHERE you attached them…but will know that you didn’t attach to the engine bay location because it will detect the difference in the battery previous to the last time it communicated with it. And could interpret the change as an issue (se text highlighted in green in the 1st screen capture from the TIS below). Attaching to the engine bay terminals keeps the IBS in the loop in regard to any changes in the battery.
BMW has been using the IBS since the debut of the e60 5 series…and the early e90 3 series and early e65 7 series (the ones before the e60 5 series) may not have an IBS…but it does use the LIN or BSD bus that acts similar to the new gen BMWs that have an IBS:
Last edited by Qsilver7; 06-08-2022 at 06:07 PM.
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