340
7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
Output State Test -
High
C to A
Figure 399 Brake Shut-off Valve circuit diagram
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
DMM set to V - DC
B+ ± 0.5 V
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
Toggling between the Low and High Output State Tests
can be done during this procedure.
If < B+, disconnect VC Gasket Breakout Harness from
gasket. Connect 500 Ohm Resistor Harness between C
and A and retest and retest Output State Test - High.
•
If equal to B+ the concern is the valve cover gasket,
UVC wiring, or Brake Shut-off Valve. Check for
short to ground or open on control circuit, or open
ground circuit.
•
If < B+ the concern is the engine harness or ECM.
Check the ECM programming and check for a short
to ground or open control circuit. Do the Actuator
Control Voltage Check at ECM (page 341) and
Harness Resistance Checks (page 342).