BMW Z4 battery replacement and charging
Z4 3.5iZ4 E85
Does a new Z4 battery need to be registered or coded?
On models with IBS battery monitoring, the replacement must be registered to the car, otherwise charging does not work properly. A larger battery additionally requires a change to the equipment list and coding. The battery of the E85 Z4 (2003-2007) does not need coding.
Why does the Z4 not charge properly after a battery replacement?
The most likely cause is that the replacement has not been registered to the car. After registration and, if needed, a reset, the car starts charging the new battery correctly.
A new battery did not help and the Z4 does not start properly - what is the fault?
Check the battery ground cable. Disconnecting the cable and cleaning the contact surfaces fixed the fault, even though replacing the battery and the starter did not help.