Husqvarna Automower 420 Technical Manual page 88

Internal diagnostics
18/19 Collision sensor prob-
lem rear/front
4 Loop sensor problem,
front
5 Loop sensor problem,
rear
32 Tilt sensor problem
27 Settings restored
28 Memory circuit prob-
lem
69 Alarm! Mower shut
down
70 Alarm! Mower
stopped
71 Alarm! Mower lifted
72 Alarm! Mower tilted
74 Alarm! Mower outside
Geofence
English - 88
6. TROUBLESHOOTING
The mower has become stuck. Free the robotic lawnmower and rec-
The body can not move freely
around the chassis.
The body is not properly secu-
red in the rubber dampers.
One of the collision sensor
magnets is missing or inverted.
The cabling to the sensor
circuit board is faulty or has
come loose.
The front loop sensor circuit
board is faulty.
The main circuit board is de-
fective.
The tilt sensor has incon-
gruous values
User settings failed to save
and the mower has been reset
to factory settings.
Resetting settings (message
27 above) has failed.
Alarm has been activated as
the mower is shut down.
Alarm activated as the mower
has been stopped.
Alarm activated as the mower
has been lifted.
Alarm activated as the mower
has been tilted.
Alarm activated as mower was
moved outside the Geofence
area.
tify the reason for it getting stuck.
Make sure the body can move freely
around the chassis.
Check that the rubber dampers are
properly attached in the body and in
the chassis.
Check the magnets. Refer to
5.1.4 Magnets for sensors on page 57.
Check the levels for A signal front and
A signal rear. Refer to 6.3 Loop signal
on page 95.
See above.
Check the levels for A signal front and
A signal rear. Refer to 6.3 Loop signal
on page 95.
Calibrate the tilt sensor. Refer to
2.6.5 Special settings on page 34.
Replace the main circuit board.
Refer to 5.8 Replacing the MCB on
page 65.
If the fault occurs repeatedly, program
the mower with the most recent main
program. Refer to 4.3.4 Programming
on page 49.
If the fault occurs repeatedly, even
using the most recent main program,
replace the main circuit board. Refer
to 5.8 Replacing the MCB on page 65.
Program the mower with the most re-
cent main program. Refer to
4.3.4 Programming on page 49.
Replace the main circuit board. Refer
to 5.8 Replacing the MCB on page 65.
Adapt the security level of the mower
in the Security menu.