|
Sounds like you may have a BSD problem. That is the communications bus that the IBS, alternator, oil level sensor and water pump communicate on.
When you have multiple faults and all the faults relate to the same bus, that's where you should look first.
FYI when you drive with the IBS disconnected the DME will set the alternator output voltage at 13.7V approx. With a working IBS and healthy battery charged no more than 80% of capacity, idle and accelerating voltage can drop below 11.8-12.8V, but when braking and coasting downhill it will spike to 14.8V. This is all normal, on BMW cars with brake energy regeneration.
It usually takes an overnight rest period for the IBS to correctly and accurately measure the battery. Every time you disconnect the battery, it has to remeasure again. That's why you thought you fixed it when you disconnected the battery for a bit.
|