September 30: LEMON manuals is back up on a temporary server! Slowness is possible

Visual/Physical Inspection

Inspect for aftermarket devices which may affect the operation of the system. Refer to Checking Aftermarket Accessories .
Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
Make sure the parking assist sensors located on the vehicle front and rear bumper are clear. Remove any snow, mud or ice that is blocking the sensors.