park brake malfunction sensor and tire pressure sensor replacement ?

Hello, You will want to ensure the sensors have failed before replacement, as they may be doing their job, letting you know your tire pressure is too low. The same applies to the parking brake malfunction sensor. Since there is no guarantee changing these parts is needed, you will need to have the vehicle diagnosed prior to estimating the repairs. For an estimate on diagnosis, see here, and select electrical or general diagnostics. https://repairpal.com/estimator/bmw/750li