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7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
ECT Operational Diagnostics
Figure 430 ECT circuit diagram
WARNING: To avoid serious personal injury,
possible death, or damage to the engine or vehicle
– comply with the following:
Be careful to avoid rotating parts (belts and fan)
and hot engine surfaces.
1. Using EST, open the D_ContinuousMonitor.ssn.
Figure 431
Continuous Monitor Test
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
2. To monitor signal voltage, run KOEO Continuous
Monitor Test. For help, see "Continuous Monitor
Test" in Section 3 (page 68).
3. Monitor ECT signal voltage. Verify an active DTC
for the ECT circuit.
4. If code is active, do step 6 and 7 to check circuit
for the ECT sensor using the following table.
•
5. If code is inactive, wiggle connectors and wires
at all suspected problem locations.
continuity is interrupted, the EST will display
DTCs related to the condition.
6. Disconnect engine harness from temperature
sensor.
NOTE: Inspect connectors for damaged pins,
corrosion, or loose pins. Repair if necessary.
7. Connect Temperature Sensor Breakout Harness
to engine harness only.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
Circuit Checks for ECT Sensor
If circuit