7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 369
WARNING: To avoid serious personal injury,
possible death, or damage to the engine or vehicle
– comply with the following:
When running the engine in the service bay, make
sure the parking brake is set, the transmission is
in neutral, and the wheels are blocked.
ECI Circuit Test – With the transmission out of g ear
and the clutch depressed w ith w heels safely blocked,
insert a harness between socket Pin 86 and 87 of the
starter relay. If the engine cranks when the start switch
is engaged, check for failed ECI relay or problems with
the ECM o r ECM wiring h arn es s.
ECI Chassis Circuit Checks (Check with key-on engine-off, ECI relay installed, and breakout box
connected.)
Test Point
Spec Comment
X3–8 to X3–7 0 V or 12 V Manual Trans – 12 V with clutch pedal down, 0 V clutch pedal up.
Auto Trans – 12 V with trans in neutral, 0 V trans in gear.
12 V ± 1.5 V
If no voltage is present with ignition switch in start position or start button
pressed, troubleshoot battery wiring.
0Vto0.6V
At crank with clutch down or auto trans i
n neutral, if ECM Pin X3–8 is at
12 V and Pin X3–23 is not at 0 V to 0.6 V, ch
eck E CM programming.
Cranking allowed. See truck Electri
cal System Troubleshooting Guide
X3–23 to X3–7
4Vto5V
Pull up voltage from ECM with key-on engine-off or running: transmission
in gear or clutch up.
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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