Webasto Air Top 3500 ST D Workshop Manual - page 23
5 Troubleshooting
Air Top 3500/5000 ST
504
Error
code
Error (group)
Additional information during PC
diagnostic
Remedy
F 07
Metering pump interrupt or short
circuit
88 Break or short circuit to +Ub
08 Short circuit to earth
Check cables, replace metering pump
Check cables, replace metering pump
F 08
Drive unit (combustion and hot air
blower) break or short circuit
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
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)
F 09
Glow plug/Flame monitor interrupt
or short circuit
8A Glow plug / Flame sensor: Break or
short circuit to + Ub
19 Glow circuit: The switched cable of the
element has a short circuit to earth
Replace glow plug / flame monitor
Replace glow plug / flame monitor
F 10
Overheating
06 The overheating fault lock-out has
tripped (heater overheated)
17 Incorrect application or illegal insulation
(ÜHS gradient too high)
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
F 11
Overheating sensor interrupt or
short circuit
AB Overheating sensor circuit break or
short circuit to +Ub
1B Overheating circuit: The switched
cable of the element has a short circuit to
earth
Replace overheating sensor
Replace overheating sensor
F 12
Heater fault lock-out
07 The heater fault lock-out has been
activated
Remove the fuse and then refit it
NOTE
The following error has occurred several
times:
Fault counter
more than 3 times
Incorrect start counter more than 9 times
Overheating counter
more than 3 times
Flame failure counter more than 2 times
F 13
Permanent heater fault lock-out
87 The permanent heater fault lock-out
has been activated
Delete the error with the PC diagnostic
NOTE
Permanent flame failure counter
more than 3 times
F 14
Overheating sensor incorrect
position
97 Incorrect position of the overheating
system (ÜHS gradient too low)
Position the overheating sensor correctly
F 15
Nominal sensor break
9B Nominal value potentiometer circuit
break or short circuit to + Ub
Check cables, replace control element
Fig. 503 Troubleshooting (page 2 of 2)