Section 4
TROUBLESHOOTING
D. CHART 7 . NO DATA LINK AND BULB CHECK OKAY
NOTE — This chart IS only to be used if
TM 9-2320-363-20-1
CHARTS
1) All basic mechanical checks and physical inspections have been performed with no problem found, and
2) Diagnosis of DDEC-II was started at step Start-1 (page 3-121 ) and you have now been referred here.
C7-1 Read Codes on the
“Check Engine” Light
l Unplug the DDR.
l Short pin A to pin M on the 12 pin
DDL connector.
l Read codes flashing out on the
“Check Engine” light.
C7-2 Check Diagnostic
Request Line
l Turn ignition off.
l Disconnect both the vehicle harness
and 6-way power harness
connectors at the ECM.
l Install a jumper wire between El
of the vehicle harness connector
and socket D of the 6-way power
harness connector.
l Read resistance between sockets
A and M on the 12 pin, DDL
connector.
C7-3 Check ECM
Connectors
l Check terminals at both the vehicle
harness and 6-way power harness
connectors (both the ECM and
harness side) for damage; bent,
corroded and unseated pins
or sockets.
WHAT TO DO NEXT
Go to C7-4 (note: if you wish to
bypass diagnosis of a potential
data link or DDR problem for
now, go to CEL-3, page 3-131.)
Go to C7-2
The Diagnostic Request line
(ckt #1451) is open or an open
or poor ground exists at pin A of
the DDL Connector. Repair
open wire or bad ground, page
3-2. Then go to C7-30.
Go to C7-3.
Replace ECM. page 4-192.
Then go to C7-30.
Repair terminals/connectors,
page 3-2. Then go to C7-30.
3-177
