Navistar International DT 466 Diagnostic/Troubleshooting Manual page 345

7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
NOTE: Complete all pin-point diagnostics (ECM to valve cover gasket connector) before removing
valve cover for under-valve-cover diagnostics.
• Turn the ignition switch to OFF before disconnecting engine wiring harness connectors from components.
See truck Chassis Electrical Circuit Diagram Manual for circuit numbers, connector and fuse locations.
•
Actuator Control Voltage Check at ECM (Connect breakout box [X2 only] to ECM and engine harness.
Engine harness is not connected to valve cover gasket. Connect 500 Ohm Resistor Harness to X2–18 and
ground. Turn the ignition switch to ON. Run Low and High Output State Test. For help, see "Diagnostic
Software Operation" in Section 3 (page 68) for procedure to run the Low and High Output State Tests.
Measure across X2–18 and ground.)
Test State/Point
KOEO
X2 - 18 to gnd
Output State Test - Low
X2 - 18 to gnd
Output State Test - High DMM set to V - DC
X2 - 18 to gnd
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Setting/Spec
DMM set to V - DC
0 V to 0.25 V
DMM set to V - DC
0 V to 0.25 V
B+ ± 0.5 V
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
Comment
If > 0.25 V, disconnect engine harness from breakout
box harness and retest.
• If > 0.25 V, run the Low and High Output State
Tests.
• If < 0.25 V, diagnose engine wiring harness.
Check for short to V
Toggling between the Low and High Output State
Tests can be done during this procedure.
If > 0.25 V, disconnect engine harness from breakout
box harness and retest.
• If < 0.25 V, diagnose engine wiring harness.
Check for short to V
• If > 0.25 V with breakout box connected only to
ECM, replace ECM.
Toggling between the Low and High Output State
Tests can be done during this procedure.
If < B+, disconnect engine harness from breakout box
harness and retest.
• If equal to B+, diagnose engine wiring harness.
Do Harness Resistance Checks (page 342).
Check for short to ground or open circuit.
• If < B+ with breakout box connected only to ECM,
replace the ECM.
or B+.
REF
or B+.
REF
341