Alpine INE-W940E Owner's Manual page 59

When there is a steep downward slope behind the
car (example)
<Screen>
<Situation of the car>
In the case of a downward slope behind the car, the
distance guides are displayed farther from the rear
bumper than the actual distance.
If there is an obstacle on the downward slope, it seems
closer than its actual position.
Also, an error may occur between the guidance and the
actual path of the car on the road surface.
Error Error
59
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