STEP/SEQUENCE
RESULT
WHAT TO DO NEXT
TM 9-2320-363-20-1
Section 4
TROUBLESHOOTING CHARTS
D. CHART -5 - "CHECK ENGINE" LIGHT ON AND NO ACTIVE CODE ON DDR
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.
This Is a digital output function.
C 5.1
Check for Short
(Ckt #528)
Turn ignition on. Observe "Check
Erratic or
Check for short to
Engine" light.
intermittent
ground on Diagnostic Request
"Check Engine" light.
(Ckt #528). Repair short.
Then to C5-30.
"Check Engine"
Go to C5-2.
light comes on
and stays on.
C 5.2
Check Light Status
Plug in DDR.
CEL reads on.
Go to C5-4.
Select switch/light status.
CEL reads off.
Go to C5-3.
C 5.3
Check for Short
(Ckt #419)
Turn ignition off.
"Check Engine"
CEL Driver line (ckt #419) is
Disconnect the vehicle harness
light comes on
shorted to ground. Repair short
connector at ECM.
and stays on.
Then go to C5-30.
Turn Ignition on (engine not running)
while at same time observing
"Check Engine" light.
"Check Engine"
Go to C5-4.
light stays off.
C 5-4
Force CEL On
Install jumper wire between socket
"Check Engine"
Go to C5-5.
B1 of vehicle harness
light comes on
connector and a good ground.
and stays on.
Observe "Check Engine" light.
"Check Engine"
The ignition line (ckt #439) is not
light stays off.
correctly wired to CEL bulb.
See if bulb has been wired into
ignition line (#439) instead of the
proper #419 wire. Correct
problem. Then go to C5-30.
Change 3 3-345.91
