TM 5-3810-307-24-1-2
Table J-2. Fault Codes (Continued)
Fault Code
Fault Description
Cause/Corrective Action
064
Open circuit flame sensor
Flame sensor signals temperature value outside of the
measurement range. Check the connecting wiring
(0.35 grey) as follows:
065
Short circuit flame sensor
Remove the control unit and disconnect the internal
connector B5.
Using multimeter set for ohms,
measure impedance between pins 10 and 12 (grey
wires) of B5: greater than 50K ohms (fault code 064)
and less than 100 ohms (fault code 065).
Flame
sensor values: 900 ohms at -13 F (-25 C), 1100
ohms at 77F (25 C).
Overheat sensor signals temperature value outside of
071
Open circuit overheat
the measurement range. Check the connecting leads
sensor
(0.35 blue) as follows:
072
Short circuit overheat
Remove the control unit and disconnect the internal
sensor
connector B5.
Using multimeter set for ohms,
measure impedance between pins 5 and 8 (blue
wires) of B5: greater than 700K ohms (fault code 071)
and less than 100 ohms (fault code 072). Overheat
sensor values: 150K ohms at -13 F (-25 C), 10k
ohms at 77F (25 C).
090
Control unit defective (internal
fault)
093
Control unit defective (RAM
Internal coolant heater control
unit error in
error)
microprocessor/memory detected.
Replace the
control unit.
094
Control
unit
defective
(EPROM error)
097
Control unit defective (power
failure)
J-42 Change-1