Navistar International DT 466 Diagnostic/Troubleshooting Manual page 339

7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
• Exhaust Gas Recirculation (EGR) actuator
• ENGINE lamp (amber)
Function
The brake shut-off valve controls pressure in the oil
gallery of the high-pressure oil rail. When the engine
brake is activated, the ECM provides power to activate
the brake shut-off valve to allow oil from the injector
oil gallery to flow to the brake oil gallery. High oil
pressure activates the brake actuator pistons to open
the exhaust valves.
The ECM removes the power from the brake shut-off
valve to deactivate the engine brake. Residual brake
gallery pressure initially bleeds from the actuator bore.
When brake gallery pressure reaches 1000 psi, the
brake pressure relief valve opens, and oil drains back
to sump.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
The brake shut-off valve consists of a solenoid and
valve assembly and is located in the center of the
high-pressure oil rail.
The ECM monitors the following criteria to make sure
certain conditions are met.
• ABS (inactive)
• RPM (greater than 1200)
• APS (less than 5%)
• EOT (greater than 60 °C [140 °F])
• Idle validation
• Operator input switches (On/Off) (power selection
– Low, Medium, High)
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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