7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 321
DTC 546
Engine brake control pressure below expected
range
• DTC 546 is set by the ECM when the brake control
pressure is less than injection control pressure by
4MPa(580psi)formorethan3.0seconds.
• DTC 546 ca n be set due to a bias low BCP sensor
or a failed BCP sensor.
• DTC546canbesetduetoanopencontrolcircuit
(power or ground), a failed brake shut-off valve, or
a failed brake shut-off valve solenoid. See “Brake
Shut-off Valve – Section 7.
• When DTC 546 is active the amber ENGINE lamp
is illuminate d.
DTC 547
Engine brake control pressure above expected
range
• DTC 547 is set by the ECM when the brake
control pressure is greater than desired brake
control pressure of 4.5 MPa (653 psi) for more
than three seconds.
• DTC 547 can be set due to an open signal ground,
V
REF
shorted to a voltage source higher than 5.5 V,
or a faulty BCP sensor.
• DTC 547 can be set due to a control circuit short
to B+ or a brake shut-off valve stuck open. See
“Brake Shut-off Valve – Sec tion 7.
• When DTC 547 is active the amber ENGINE lamp
is illuminated.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• 3-Banana Plug Harness
• 500 Ohm Resistor Harness
• VC Gasket Breakout Harness
• UVC Pressure Breakout Harness
• Breakout Box
• Terminal Te st Adapter Kit
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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