TM 9-4520-272-14&P
0008 00
burner access door and ensure that
notify unit maintenance.
flame sensor is securely installed in
flame sensor tube.
Step 2. If problem has not been
corrected, notify unit maintenance.
15. Heater starts, shuts down,
Step 1. This fault code indicates a loss
Step 1. Check to ensure that heater
and displays fault code: H121
has adequate fuel. If any fuel loss is
occurred during operation. Turn power
observed, notify unit maintenance.
switch OFF. Inspect engine bay, fuel
access, and burner areas for any signs
of fuel loss.
Step 2. Secure any loose connectors
ensure that all wires are secured and
on alternator. If any wires are cut or
are undamaged.
damaged, notify unit maintenance.
Step 3. If alternator belt is loose or if
not broken or damaged.
broken notify unit maintenance.
Step 4. Ensure that flexible coupling is
Step 4. If flexible coupling assembly
not broken or damaged.
is loose or damaged notify unit
maintenance.
Step 5. If problem has not been
corrected, notify unit maintenance.
16. Heater starts, shuts down,
Step 1. This fault code indicates that the
Step 1. If diesel engine starter is not
and displays fault code: H122
turning during heater startup or if
during engine crank. During heater
unsure and problem persists, contact
startup, determine if diesel engine
unit maintenance.
starter is turning. If unsure, and problem
persists, contact unit maintenance.
Step 2. Turn power switch OFF. Inspect
Step 2. Secure any loose wires on
wiring on alternator and ensure that all
alternator. If wires are cut or
wires are secured and are undamaged.
damaged, notify unit maintenance.
Step 3. If alternator belt is damaged
not broken or damaged.
or broken, notify unit maintenance.
Step 4. Ensure that flexible coupling is
Step 4. If flexible coupling is broken
not broken or damaged.
or damaged, notify unit
maintenance.
Step 5. If problem has not been
corrected, notify unit maintenance.
17. Heater starts, shuts down,
Step 1. This fault code indicates that
Step 1. Secure wiring harness
and displays fault code: H561
there is an open circuit detected at the
connector on relay box assembly as
engine throttle stop solenoid relay driver
required. If any wires are cut or
K2. Turn power switch OFF. Open
damaged, notify unit maintenance.
engine bay access door and inspect
relay box assembly to ensure that
Step 2. If problem has not been
wiring harness is not damaged and that
corrected, notify unit maintenance.
the connector is engaged securely.
18. Heater starts, shuts down,
Step 1. This fault code indicates that the
Step 1. Secure connection between
and displays fault code: H421
system is not receiving a proper
the operator control box and the
response from the operator control box.
operator control box cable. Notify
Turn power switch OFF. Ensure that the
unit maintenance if connector is
0008 00-5