STEP/SEQUENCE
RESULT
WHAT TO DO NEXT
TM 9-2320-363-20-1
Section 4
TROUBLESHOOTING CHARTS
D. CHART - 9 - DIAGNOSTIC REQUEST SWITCH INOPERATIVE
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 9-1
Check Diagnostic
Request Circuit
Turn ignition on/engine
Display reads "ON".
Go to C9-2.
not running.
Plug in DDR.
Select "Switch/Light STATUS"
Depress and hold diagnostic
Display reads "OFF".
Diagnostic Request Line (#528)
request switch.
is open, or is not being grounded
when switch is depressed. Check
#528 wire and ground for
diagnostic request switch. Repair
problem then go to C9-30.
Observe "Diagnostic Request"
Display reads "N/A".
ECM is not configured for
Status on DDR.
diagnostic request operation.
Refer to Application Manual.
C 9-2
Check SEL/CEL Bulb
Turn ignition off.
Bulb is okay.
Go to C9-3.
Remove CEL and SEL Bulb,
check to see if it is burned out
Bulb is not okay.
Replace bulb(s) then go to C9-30.
or damaged.
C 9-3
Check 12124V
Ignition Line
Turn ignition off.
Disconnect vehicle harness
Less than
5 Amp fuse (or circuit breaker) is
connector at ECM.
11.5V (12V system)
blown and/or ignition line is open
Read voltage at cavity B3 (#439).
or 23V (24V system).
or shorted to ground.
Greater than 11.5V
Ckt #419 or #509 is open.
(12V system) or 23V
Repair open and go to C9-30.
(24V system).
Change 3 3-345.111
