380 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
IDM CAN 2 Checks (Remove ECM following procedure in the Engine Service Manual.Mea
sure directly to
ECM pins only.)
NOTE: Use IDM ground pins (X3–1, X3–2, X3–3, X3–22, or X3–26) only for th
is test.
IDM X3–30 to gnd
1.85 MΩ
±0.20 MΩ
If > spec, replace the IDM.
IDM X3–31 to gnd
1.85 MΩ
±0.20 MΩ
If > spec, replace the IDM.
IDM X3–30 to X3–31
120 Ω If > 120 Ω,replacetheIDM.
IDM X3–32 to gnd
<5Ω If > 5 Ω,replacetheIDM.
IDMhousingtognd
<5Ω If > 5 Ω,replacetheIDM.
1
Connector 9260 is a 2-wire connector usually located in the battery box. Pin A is the chassis ground connection for
the ECM and IDM. Refer to truck Chassis Electrical Circuit Diagram Manual for complete chassis side ECM and IDM
ground circuit information.
Operational Checks for CMPO and CKPO (Check with breakout box connected to ECM and engine
harness.)
Test Point
Engine Cranking
Low Idle High Idle
Comment
X1–24 to X1–6
130–225 rpm
2
@
130–225 rpm
700 rpm
2
@ 700
rpm
2750 rpm
2
@2750
rpm
Set DMM to
DC-rpm
2
X1–19 to X1–6
130–225 Hz @
130–225 rpm
700 Hz @ 700
rpm
2.75 kH Z to 3.00
kHz
Set DMM to DC-Hz
Diagnostic Trouble Codes
DTC 543 = ECM / IDM communication fault
DTC 551 = IDM CMPO signal inactive
DTC 552 = IDM incorrect CMPO sign
al signature
DTC 553 = IDM CKPO signal inactive
DTC 554 = IDM incorrect CKPO signal signature
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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