The phrase "to raise the suspension" means to make a vehicle's ride higher by increasing the height between the wheels and the body of the vehicle. Full definition
And if you were to encounter some rough terrain, you can raise the suspension for improve ground clearance. (motor1.com)
It brings an electronic differential lock with four modes — for dry roads, mud, snow and sand — as well as raised suspension and mud and snow tyres. (autoexpress.co.uk)
A serious off - road mode raises the suspension and allows for approach and departure angles of 27 and 24 degrees. (extremetech.com)