TM 5-3810-307-24-1-2
Table J-2. Fault Codes (Continued)
Fault Code
Fault Description
Cause/Corrective Action
015
Too many overheats
The coolant heater control unit is interlocked after
three consecutive overheating events (codes 012,
013, and 014). Correct the overheat fault. Cancel the
control unit interlock and clear error memory by
pressing both "L" buttons simultaneously on the Fault
Code Retrieval Device.
020
Open circuit glow pin
Check glow pin (nominal value: 2 ohms) and replace if
necessary. Remove the control unit and disconnect
the internal connector B5. Using multimeter set for
021
Short circuit glow pin
ohms, check for continuity between pin 3 (white wire)
and pin 4 (brown wire) on the coolant heater control
unit internal connector B5. If OK, replace control unit.
033
Combustion air blower motor
Speed deviation for longer than 60 seconds. Nominal
value: 5600 rpm (full load), 1850 rpm (part load).
Check blower motor: Apply supply voltage to motor.
Connect (+) to 1.5 black and (-) to 1.5 orange. If
motor does not turn, replace the blower motor.
Check blower motor sensor supply. Switch on coolant
heater and using multimeter set for volts DC, measure
voltage between output pin 13 (0.25 red) and pin 14
(0.25 green) at the control unit internal connector B5.
Nominal value is 8 VDC. If voltage incorrect, replace
control unit.
Check blower motor sensor. Using multimeter set for
volts DC, measure voltage between pin 15 (0.25
violet) and pin 14 (0.25 green) on internal connector
B5 with blower motor running. Nominal value is 4
VDC (+ 0.3 volts) average value (8 VDC square-wave
signal). If voltage is incorrect, replace blower motor.
If OK, replace coolant heater control unit.
037
Water pump is not working
Check water pump for proper operation.
042
Water pump short circuit
Check water pump and electrical leads.
043
Short circuit external
Using multimeter, check wiring to fuel metering pump
components
and seven day timer for possible short circuit. Also
check all connected components for evidence of short
circuit (maximum current draw is 6 Amps). Replace
defective components.
Using multimeter, check green wiring of coolant
047
Short circuit fuel metering
heater control unit connector B1 and leads to fuel
pump
metering pump for possible short circuit. Nominal
value: approximately 20 ohms. If defective, replace
048
Open circuit fuel metering
fuel metering pump.
pump
J-40 Change-1
