Webasto Thermo Pro 90, Service Installations

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