BMW F97 - Steering System Details

F97/F98�Complete�Vehicle
4.�Powertrain
38
Temperature�monitoring
A�total�of�3�temperature�sensors�are�installed.�The�temperature�of�the�control�unit�(driver�output�stage),
the�temperature�of�the�electric�motor�and�the�transmission�oil�temperature�are�monitored.
The�temperature�thresholds�are:
• Control�unit�85°C�(185°F)
• Electric�motor�160�°C�(320�°F)
• Oil�temperature�190°C�(374�°F)
4.3.8.�Service�information
• If�the�M�GHAS�control�unit�is�replaced,�coding�(activation�of�a�vehicle-related�characteristic
curve)�and�then�initial�calibration�are�necessary,�after�which�the�fault�memory�must�be�erased.
• After�the�replacement�of�the�entire�M�rear�axle�differential�a�calibration�must�be�performed�and
then�the�fault�memory�must�be�deleted.
• If�the�electric�motor,�the�electric�motor�and�intermediate�gearing�or�the�oil�temperature�sensor
is�replaced,�erasing�the�fault�memory�is�all�that�is�required.
The�rear�differential�fluid�is�currently�replaced�at�2000km�(1200�mile�running-in�check)�and�every�3rd
engine�oil�change.
Because�of�the�change�of�clutch�plate�material�to�one�with�carbon�content�on�the�F90�and�F97/F98,
a�new�differential�fluid�is�used.�The�initial�filling�is�with�Fuchs�Titan�5037B.
Current�rear�axle�differential�box�oil�recommendations�and�capacities�can�be�found�in�the�current
documentation�of�the�BMW�workshop�information�systems.
If,�due�to�a�fault,�the�M�GHAS�lock�function�is�switched�off�or�fails,�a�blocked�differential�is�automatically
reopened�as�the�lock�function�is�not�self-locking.�The�driver�is�warned/informed�and�the�following
effects�can�be�expected:
1.�Deterioration�of�traction�with�dynamic�driving�style�and�low�coefficients�of�friction,
particularly�with�different�coefficients�of�friction,�left/right.
2.�Possible�deterioration�of�stability�in�dynamic�driving�situations.