STEP/SEQUENCE
RESULT
WHAT TO DO NEXT
TM 9-2320-363-20-1
Section 4
TROUBLESHOOTING CHARTS
D. CHART 4 - NO "CHECK ENGINE" LIGHT DURING BULB CHECK OR CANNOT CLEAR CODES (Cont'd)
C 4-4
Check for Open
Remove jumper wire. With ignition
Less than
The ignition line (ckt #439) is
on, read voltage on vehicle
10.0 volts. (12V system)
open. Repair open Then go
harness connector, socket B3
20.0 volts (24V system).
to C4-30.
(red lead) to a good ground
(black lead).
Greater than
Go to C4-5.
or equal to 10.0 volts.
(12V system) 20.0 (24V
system).
C 4-5
Check for Bat +
Turn ignition off.
Less than
Either one of the 20 Amp ECM
Disconnect the 5-way power
+10.0 volts on
fuses (or circuit breadkers) Is
harness connector.
any reading
blown and/or the Battery Power
Read voltage at the 5-way power
line (s) (ckt #240 or #241) has
harness connector. Socket A (red
an open or short to ground.
lead) to a good ground (black
Check that the battery power
lead).
(Circuits #240 and #241) are
Repeat voltage readings on 5-way
not switched off when the ignition
power harness connector, keeping
Is turned off (See note below).
the black lead to a good ground
Repair problem. Then go
and the red lead to Socket C.
to C4-30.
Greater than
Go to C4-6.
or equal to
*10.0 volts on
readings.
*NOTE:
Engine update information may not update if main ECM power (circuits #240 and #241) is switched
off with/or before ignition.
*20 volts for 24 volt system.
Change 3 3-345.87
