Webasto Thermo Pro 90 Series Service Installations page 18

5 Malfunctions and troubleshooting
Fault Fault
code code
(ana- (hexa-
logue) decimal)
F09 F8A Glow plug / flame mo-
or F19 nitor short circuit
9* F99
F10 F06 Heating unit over-
or F07 heated
10* F86
F11 F0B Coolant pump short
or F8B circuit
11*
F12 F16 Battery disconnector or
or electronic battery
12* switch short-circuit
F13 F13 Vehicle fan power cir-
or F30 cuit short circuit
13*
F14 F1B Overheat sensor short
or FAB circuit
14*
F15 F2E The glow/ignition-ele-
or ment power circuit is
15* defective
F16 F4F Exhaust gas tempera-
or F3B ture too high
16*
F17 F31 Exhaust-gas tempera-
or F4D ture sensor: open or
17* short circuit
504
*: Indicator lamp of control element flashing: Number of long flash pulses after 5 short flash pulses
Error message
Wiring
Glow plug defective
Heating unit overheated
Overheating protection
defective
Wiring
U4840 coolant pump
defective
Wiring
Electronic battery switch
defective
Wiring
Vehicle fan relay
Wiring
Overheating protection
sensor defective
Wiring
Glow plug defective
Exhaust gas temperature
sensor defective
Heater fouled
Wiring
Exhaust gas temperature
sensor defective
Possible causes
Check wiring for damage, break and short-circuit
Check operation of glow plug, replacing if
necessary
Check coolant level, bleed coolant circuit
Check operation of coolant pump
Check wiring for damage, break and short-circuit
Check operation of overheating protection,
replacing if necessary
Check wiring for damage, break and short-circuit
Replace coolant pump
Check wiring for damage, break and short-circuit
Check power intake of battery disconnector
Check wiring for damage, break and short-circuit
Check wiring for damage, break and short-circuit
Check operation of vehicle fan relay (K5, see
Section 11), replacing if necessary
Check wiring for damage, break and short-circuit
Check operation of overheating protection sensor,
replacing if necessary
Check glow plug wiring for damage, break and
short-circuit
Check operation of glow plug, replacing if
necessary
Check wiring for damage, break and short-circuit
Check operation of exhaust gas temperature
sensor, replacing if necessary
•
•
•
Check wiring for damage, break and short-circuit
Check operation of exhaust gas temperature
sensor, replacing if necessary
Thermo Pro 90
Recommended action in workshop
Check burner
Visual inspection with cleaning, replacing
burner if necessary
Visual inspection with cleaning and replacing
burner head if necessary
Visual inspection with cleaning of inner
surface of heat exchanger (replace if
necessary)