Ecm / Idm Communications (Electronic Control Module / Injector Driver Module) - Navistar International DT 466 Diagnostic/Troubleshooting Manual

7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
ECM / IDM Communications (Electronic Control
Module / Injector Driver Module)
Figure 421 Function diagram for the ECM / IDM communication system
The function diagram
communication system includes the following:
• ECM
• IDM
• Exhaust Gas Recirculation (EGR) drive module
• Crankshaft Position Output (CKPO) signal
• Camshaft Position Output (CMPO) signal
• Controller Area Network (CAN 2) datalink
• ENGINE lamp (amber)
Function
The ECM provides two output channels to aid the IDM
with engine speed and position signals. The CKPO
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
for the ECM / IDM
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
and CMPO channels are in phase with the CKP and
CMP signals received by the ECM.
The ECM and IDM are in continuous communication.
The CKPO and CMPO signals are generated when
the ECM switches these circuits to ground. The IDM
uses these signals for engine speed and timing.
The CAN 2 datalink is a bidirectional communication
line between the ECM, IDM, and EGR drive module.
The ECM, IDM, and EGR drive module use the
datalink to send operating strategies,
information, diagnostic demands, and Diagnostic
Trouble Codes (DTCs).
NOTE: The engine will not operate without the CAN 2
datalink, CKPO, or CMPO signal.
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sensor