DIAGNOSIS Error 6 is a false positive from the front bumper sensor. The microswitch inside the bumper housing is stuck or misaligned.
FIX Press the bumper firmly with your hand all around its edges. You should hear a distinct click. If it feels mushy or doesn't click, the bumper needs reseating. Push the top edge of the bumper cover inward and upward to unclip it. Check the white plastic lever that activates the microswitch for debris or damage.
IF THAT DIDN'T WORK The bumper cable connector inside the mower body can come loose. Open the main compartment (power off first). Locate the connector near the front-left corner and ensure it is fully seated.
HEADS UP Do not disable the collision sensor. A misaligned bumper is a safety hazard and will cause constant interruptions.