Navistar International DT 466 Diagnostic/Troubleshooting Manual page 488

484 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
CAUTION: To avoid engine damage, turn the ignition switch to OFF before disconnecting the connector or
relay for the IDM. Failure to turn the ignition switch to OFF will cause a voltage spike and damage to electrical
components.
Voltage Checks at IDM – Key-On Engine-Off (Check with IDM power relay installed. Disconnect IDM X3
connector. Ground Pin X3–27 using Terminal Test Pin Adapter and harness to activate relay and check at
harness connector. Inspect for bent pins or corrosion.)
Test Point Spec
IDM X3–7 to gnd 12 V ± 1.5 V
IDM X3–1 to gnd 0 V to 0.25 V
IDM X3–2 to gnd 0 V to 0.25 V
IDM X3–3 to gnd 0 V to 0.25 V
IDM X3–22 to gnd 0 V to 0.25 V
IDM X3–26 to gnd 0 V to 0.25 V
IDM X3–27 to gnd 0 V to 0.25 V
IDM X3–8 to gnd 12 V ± 1.5 V
IDM X3–4 to gnd 12 V ± 1.5 V
IDM X3–23 to gnd 12 V ± 1.5 V
IDM X3– 24 to gnd 12 V ± 1.5 V
IDM X3–25 to gnd 12 V ± 1.5 V
WARNING: To avoid serious personal injury, possible death, or damage to the engine or vehicle,
always disconnect main negative battery cable first. Always connect the main negative battery cable
last.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Comment
Power from ignition switch to IDM. If no voltage, see truck Chassis
Electrical Circuit Diagram Manual.
Ground – voltage reading indicates poor ground to battery. See truck
Chassis Electrical Circuit Diagram Manual.
Ground – voltage reading indicates poor ground to battery. See truck
Chassis Electrical Circuit Diagram Manual.
Ground – voltage reading indicates poor ground to battery. See truck
Chassis Electrical Circuit Diagram Manual.
Ground – voltage reading indicates poor ground to battery. See truck
Chassis Electrical Circuit Diagram Manual.
Ground – voltage reading indicates poor ground to battery. See truck
Chassis Electrical Circuit Diagram Manual.
IDM grounds relay through internal transistor. Expect 0 V with X3–27
grounded. If voltage is present, check Terminal Test Pin Adapter and
jumper.
Power from relay to IDM. If no voltage, check fuses. If a fuse is blown,
check for short to ground. If fuses are good, check for open circuit
between 87 and X3–8. See truck Chassis Electrical Circuit Diagram
Manual for circuit numbers, connector and fuse locations.
Power from relay to IDM. If no voltage, check for open between Pin
X3–4 and 87 on IDM relay. See truck Chassis Electrical Circuit Diagram
Manual for circuit numbers, connector and fuse locations.
Power from relay to IDM. If no voltage, check for open between Pin
X3–23 and 87 on IDM relay. See truck Chassis Electrical Circuit
Diagram Manual for circuit numbers, connector and fuse locations.
Power from relay to IDM. If no voltage, check for open between Pin
X3–24 and 87 on IDM relay. See truck Chassis Electrical Circuit
Diagram Manual for circuit numbers, connector and fuse locations.
Power from relay to IDM. If no voltage, check for open between Pin
X3–25 and 87 on IDM relay. See truck Chassis Electrical Circuit
Diagram Manual for circuit numbers, connector and fuse locations.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.