Webasto Coolant - Fault Codes

Fault Codes
NOTE: Not all Webasto coolant heaters show fault codes.
Fault
Code
Error
Message
Possible Cause
Recommended
Action
Applicable Heaters
F00
or
0*
No error
Heater Lock-
out
1
• Fuses
• Electrical wiring
• Heater lock-out
• Control Unit Defective
• Check fuses
• Check control
element
• Check W-bus connections (yellow
Thermo Pro 50 ECO
Thermo Pro 90
F01
or
1*
No start
• Fuel system
• Combustion air/exhaust pipe
• Burner unit
• Check fuel level
• Check fuel filter
• Check fuel extractor and fuel line for
leaks
• Bleed fuel system
• Check combustion air/exhaust pipe
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90
F02
or
2*
Flame failure/
Flame abort
• Fuel system
• Burner unit
• Check fuel level
• Check fuel filter
• Check fuel extractor and fuel lines for
leaks
• Bleed fuel system
• Clean/replace burner
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90
F03
or
3*
Supply Volt-
age Too High/
Low
• Power supply
• Check battery
• Check electrical connections
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90
F04
or
4*
Premature
flame detec-
tion
• Foreign light detected during
run-up or run-down
2
• Flame sensor defective
• Exhaust temperature sensor
defective
1
• Check flame monitor
• Check exhaust gas temperature sen-
sor
1
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90
F05
or
5*
Flame sensor
defective
2
• Defective Flame sensor • Check flame sensor
Thermo 230/300/
350
Thermo 50
Thermo 90 ST
F06
or
6*
Temperature
sensor open-
or short-cir-
cuit
• Wiring
• Coolant temperature sensor
defective
• Check wiring/sensor for resistance
• Check operation of sensor
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90
F07
or
7*
Metering/Fuel
pump defec-
tive
Fuel solenoid
defective
2
• Wiring
• Defective pump
• Check wiring for damage
• Check fuel pump for operation
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90
F08
or
8*
Combustion
air fan defec-
tive/blocked
• Wiring
• Blockage
• Defective fan
• Check wiring for damage
• Remove blockage
• Replace fan
Thermo 230/300/
350
Thermo 50
Thermo Pro 50 ECO
Thermo 90 ST
Thermo Pro 90