Section 4
TM 9-2320-363-20-1
TROUBLESHOOTING CHARTS
D. CHART4. NO “CHECK ENGINE” LIGHT DURING BULB CHECK OR CANNOT CLEAR CODES (Cont’d.)
STEP/SEQUENCE
C4-4 Check for Open
l Remove jumper wire. With ignition
on, read voltage on vehicle
harness connector, socket B3
to a good ground.
C4-5 Check for Bat +
l Turn ignition off.
l Disconnect the 6-way power
harness connector.
l Read voltage at the 6-way power
harness connector. Socket A to a
good ground.
l Repeat voltage readings on 6-way
power harness connector, keeping
the black lead to a good ground
and the red lead to.
—socket B
—socket E
—socket F
WHAT TO DO NEXT
The ignition line (ckt #439) is
open. Contact Direct Support.
Then go to C4-30.
G o t o C 4 - 5 .
Either one of the 240 Amp, ECM
fuses is blown and/or the
Battery Power line(s) (ckt #240
or #241) has an open or short to
ground. Check that the battery
power (Circuits #240 and #241 )
are not switched off when the
ignition is turned off (See note
below). Repair problem.
Then go to C4-30.
Go to C4-6.
l NOTE: Historical codes will not clear and engine hours/fuel consumption values will not update if main ECM power (circuits
#240 and #24 1 ) is switched off with ignition.
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