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
NOTE - This chart is only to be used if:
1)
All basic mechanical checks and physical inspections have been performed with no problem found, and
2)
Diagnosis of DDEC-III was started at step Start-1, pg 3-345.41 and you have now been referred here.
C 4-1
Try to Force CEL On
Plug in DDR.
"Check Engine"
Go to C4-2.
Turn ignition on.
light is still off.
Select activate ECM outputs.
Activate Check Engine Light.
"Check Engine"
Go to C4-4.
light is still on.
C 4-2
Check for Ignition
Remove jumper wire.
Less than *10.0 volts
The 5 Amp, ignition fuse (or
Read voltage on vehicle harness
circuit breaker) is blown and/or
connector, socket B3 (red lead)
ignition wires are open or
to a good ground (black lead)
shorted to ground, and/or the
with the ignition on and engine
ignition line (ckt #439) is shorted
off.
to ground or is not wired to
switch ignition source (See note
below). Repair Problem. Then
go to C4-30.
Greater than
Go to C4-3.
or equal to *10.0 volts.
C 4-3 CEL Drive line and Bulb
Check
Turn ignition off.
Bulb is
CEL Driver line (ckt #419) or
Remove CEL bulb and check
okay.
ground line (ckt #150) is open.
whether it's burned out or
Repair open. Then go to C4-30.
otherwise damaged.
Bulb is
Replace bulb. Then go to C4-30.
not okay.
*NOTE:
Inactive codes will not clear and engine hours/fuel consumption values will 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 3-345.85
