7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 379
Harness Resistance Checks (Turn the ignition switch to OFF. Check with breakout b
ox connected [X1 and
X2] to engine harness only. IDM checked at harness connector X3 using terminal t
est pins. IDM pins are
numbered on the mating end of the connector.)
NOTE: Test points are from E CM to IDM.
ECM X1–19 to IDM X3–5 < 5 Ω If > 5 Ω, check for open in harness.
ECM X1–24 to IDM X3–10 < 5 Ω If > 5 Ω, check for open in harness.
ECM X2–6 to IDM X3–30 < 5 Ω If > 5 Ω, check for open in harness.
ECM X2–13 to IDM X3–31 < 5 Ω If > 5 Ω, check for open in harness.
ECM X2–12 to IDM X3–32 < 5 Ω If > 5 Ω, check for open in harness.
Resistance Checks – CAN 2 Datalink (Turn the ignition sw
itch to OFF. Connect breakout box to ECM
and chassis harness.)
ECM X2–6 to gnd 3 MΩ ±0.1
MΩ
If > spec, check for short to ground or another circuit. Check
ECMandIDMseparately.
If < spec, check for open circuit on CAN 2+. Check ECM
and IDM separately.
ECM X2–13 to gnd 3 MΩ ±0.1
MΩ
If > spec, check for short to ground or another circuit. Check
ECMandIDMseparately.
If < spec, check for open circuit on CAN 2+. Check ECM
and IDM separately.
ECM X2–6 to X2–13 60 Ω If > 60 Ω, check for open circuit on CAN 2+
and CAN 2-.
Check ECM and IDM separately. Do Resis
tance C hecks –
ECM CAN 2 Circuit and Resistance Check
s–IDMCAN2.
ECM X2–12 to gnd < 5 Ω If > 5, check for open on CAN 2 shield (IDM Pin X3–32).
Check ECM and IDM separately. Do Resistance Checks –
ECM CAN 2 Circuit and Resistance Checks – IDM CAN 2.
Resistance Checks – ECM CAN 2 Circuit (Remove ECM following p r ocedure in the Engine Service
Manual. Measu re directly to ECM pins only. )
NOTE: Use E CM ground pins (X3–7 or X3–6) only for this test.
ECM X2–6 to gnd 3.9 MΩ ±0.2
MΩ
If > spec, rep lace the ECM .
ECM X2–13 to gnd 3.9 M Ω ±0.2
MΩ
If > spec, rep lace the ECM .
ECM X2–6 to X2–13 120 Ω If > spec, rep lace the ECM .
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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