7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 541
The ECM supplies V
REF
at Pin X1–14 (engine
connector) and at X4–4 (chassis connector) when the
ignition switch is on.
Fault Detection / Management
There are no DTCs for V
REF
.WhenaV
REF
circuit fault
occurs in a sensor, the ECM may set an out of range
high or low code. Multiple high or low codes are
indicators of a V
REF
or signal ground fault condition.
When a V
REF
signal is shorted to ground, shorted
to ground occurs, the ECM will reset and cause a
stumble.
When the ECM se ts multiple se ns or DTCs, the V
REF
circuit is open or shorted, or the signal ground circuit
is open. To determine if the V
REF
circuits are the cause,
complete the pin-point diagnostics check.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• Breakout Harness
• Breakout Box
• Terminal Te st Adapter Kit
NOTE: After removing connector, inspect for
damaged pins, corrosio n, or lo ose pins . Repair
as required.
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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