BMW X3 Owners Manual: Carry out reset
Reset the system after each adjustment of the tire inflation pressure and after every tire or wheel change.
On the Control Display and on the vehicle:
1. "Vehicle info"
2. "Vehicle status"
3. 
"Perform reset"
4. Start the engine - do not drive off.
5. Reset tire inflation pressure: "Perform reset".
6. Drive away.
The tires are shown in gray and the status is displayed.
After driving faster than 19 mph/30 km/h for a short period, the set tire inflation pressures are accepted as reference values. The reset is completed automatically while driving.
The progress of the reset is displayed.
After a successfully completed Reset, the wheels on the Control Display are shown in green and "Tire Pressure Monitor (TPM) active" is displayed.
You may interrupt this trip at any time. When you continue the reset resumes automatically.
Status display
The current status of the Tire Pressure Monitor
TPM can be displayed on the Control Display,
e.g., whether or not the TPM is active.
1. "Vehic ...
Low tire pressure message
The yellow warning lamp lights
up. A
Check Control message is displayed.
There is a flat tire or a major loss in
tire inflation pressure.
...
Other materials:
BMW X3 Service & Repair Manual > Rear sub-frame: Removing and installing complete rear axle support
WARNING: Danger of injury!
Failure to comply with the following instructions may result in the vehicle
slipping off the vehicle hoist and critically injuring other persons.
Load the luggage compartment with a minimum of 100 kg before
lowering/removing the rear axle support.
When supporting ...