When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Welcome to the Forum…the only thing I can think of is that the IPC battery voltage is measured by the BCM and if the BCM ground is “elevated” that can raise the voltage…if you are charging at 14 volts and say the ground is at 2 volts that 14 volts will be elevated to 16…the 2 grounds are pin 12 J1 connector (black/white) and pin e12 on J4…seems your battery and charging voltage are OK with a 0.1 volt voltage drop on the positive side of the charging system…I would back probe at the BCM with engine running…you can also check both grounds…G202 and 104…G202 is base of right A pillar and 104 is under the battery tray…normally at 16 volts you would get a DIC message for high battery voltage…also helps if we know at least your model year.
It shouldn’t be reading 16 volts and if your electrical experience is just checking voltage with a DVOM best to seek out an auto electric repair shop…you can remove the 4 connectors on the BCM 2 of which are lever lock and 2 bolted bolted in on the front and back of the BCM..you will have to remove the BCM to access X4…disconnect the battery and remove all 4 and then use some electrical contact cleaner like DeOxit and check for any type of corrosion or damage…reinstall all 3 and connect the battery and see what happens…if you had a factory level or equivalent scan tool I’m sure there are some voltage data PIDS you can observe in the BCM that might point to this high voltage.
voltage issue
