Idm Pwr Circuit Operation - Navistar International DT 466 Diagnostic/Troubleshooting Manual

480 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS

IDM PWR Circuit Operation

Figure 473 IDM PWR circuit diagram
The IDM is grounded to the battery negative terminal
at IDM Pins X3-1, X3-2, X3-3, X3-22 and X3-26.
The IDM receives V power at Pin X3-7. The power
IGN
signals the IDM to provide a ground path from Pin
X3-27 to 85 to switch the IDM main power relay.
Switching the relay provides power from the battery
positive terminal through a fuse and relay contacts
30 and 87 to Pins X3-4, X3-23, X3-24 and X3-25.
Switching the relay also supplies power through a
fuse to Pin X3–8 logic power. See truck Chassis
Electrical Circuit Diagram Manual for circuit numbers,
connector and fuse locations.
Fault Detection / Management
The IDM internally monitors battery voltage. When the
IDM continuously receives less than 7 V or more than
16 V a Diagnostic Trouble Code (DTC) will be set.
IDM PWR Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the
flashes from the amber and red ENGINE lamp.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
DTC 525
IDM fault
• DTC 525 is set by the ECM when there is an
internal IDM failure.
replace the IDM.
• When DTC 525 is active the amber ENGINE lamp
is illuminated.
DTC 523
IDM V
• DTC 523 is set by the ECM when the voltage from
V
• DTC 523 can be set due to poor connections
between the IDM Pin X3-7 and the V
• DTC 523 will not illuminate the amber ENGINE
lamp
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
When DTC 525 is set,
voltage low
IGN
is less than 7 V.
IGN
.
IGN