Webasto Air Top Evo 3900 Workshop Manual page 24

5 Troubleshooting
Error Error (group)
code
F 07 Metering pump interrupt or
metering pump short-circuit
F 08 Fan motor interrupt or fan motor
short-circuit or fan motor overload
or fan motor blocked
F 09 Glow plug interrupt or glow plug
short-circuit
F 10 Overheating
F 11 Overheating sensor interrupt or
overheating sensor short circuit
F 12 Heater unit lock-out
F 14 Overheating sensor incorrect
position
F 15 Setpoint generator short circuit
504
Additional information during PC
diagnostic
88 Break or short circuit to +Ub
08 Short circuit to earth
89 Break or short circuit to +Ub
09 The switched drive unit cable
(combustion and hot air blower) has a
short circuit to earth or the drive unit is
overloaded
15 Burner motor block guard has tripped
95 Burner motor not turning easily sensor
has tripped
8A Glow plug/Flame monitor: Break or
short circuit to +Ub
19 Glow circuit: The switched cable of the
element has a short circuit to earth
06 The overheating fault lock-out has
tripped (heater overheated)
17 Incorrect application or illegal insulation
(OHS gradient too high)
AB Overheating sensor circuit:
break or short circuit to +Ub
1B Overheating sensor circuit:
the switched cable of the element has a
short circuit to earth
07 The permanent heater fault lock-out
has been activated
97 Incorrect position of the overheating
sensor (OHS gradient too low)
9B Nominal value potentiometer circuit
break or short circuit to + Ub
Fig. 503 Troubleshooting (page 2 of 2)
Air Top Evo 3900/5500
Troubleshooting
Check cables, replace metering pump
Check cables, replace metering pump
Replace drive unit (combustion and hot air
blower)
Eliminate the cause of the blockage /
difficulty in movement
Replace drive unit (combustion and hot air
blower)
Replace glow plug / flame monitor
Replace glow plug / flame monitor
Find and remove the cause of the
overheating
NOTE
If no other cause can be found for the
overheating, the pressure losses caused
by the hot air distribution (too many
resistance points) are too high or a hot air
filter is soiled
Replace overheating sensor
Replace overheating sensor
Heater unit is switched on,
Fault code F12 is shown.
Remove fuse.
Switch off heater unit with heater control.
Insert fuse again after more than 2
seconds.
Switch on heater unit again with heater
control.
NOTE
The following error has occurred several
times:
Fault counter more than 5 times
Incorrect start counter more than 9 times
Flame failure counter more than 5 times
Position the overheating sensor correctly
Check cables, replace control element