Ecm / Idm Pin-Point Diagnostics - Navistar International DT 466 Diagnostic/Troubleshooting Manual

376 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS

ECM / IDM Pin-Point Diagnostics

Figure 423 ECM / IDM circuit diagram
CAUTION: To avoid engine damage, turn the ignition switch to OFF before disconnecting the connector or
relay for the ECM and IDM. Failure to turn the switch to OFF will cause a voltage spike and damage to electrical
components.
ECM Connector Voltage Checks to Chassis Ground (Check with breakout box connected [X1 and X2]
to engine harness only. Inspect for bent pins or corrosion. Turn the ignition switch to ON. Note: ECM is
not connected. IDM output is checked through the wiring harness.)
Test Point
X2–6 to gnd
X2–13 to gnd
X1–19 to gnd
X1–24 to gnd
X2–12 to gnd
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Spec Comment
1 V to 4 V Digital signal. If no voltage check for open or short to ground
and do resistance checks to chassis ground, harness
resistance checks, and resistance checks - IDM CAN2
checks.
1 V to 4 V Digital signal. If no voltage check for open or short to ground
and do resistance checks to chassis ground, harness
resistance checks, and resistance checks - IDM CAN2
checks.
11 V to 12 V If < 11 V to 12 V, check for open or short to ground. Check
IDM power relay.
11 V to 12 V If < 11 V to 12 V, check for open or short to ground. Check
IDM power relay.
0 V Ground, no voltage expected
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.