Diesel Engine Speed Control System - Jeep Cherokee 2000 Service Manual

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VEHICLE SPEED CONTROL SYSTEM
DESCRIPTION AND OPERATION

DIESEL ENGINE SPEED CONTROL SYSTEM . . . . 1

DESCRIPTION AND OPERATION
DIESEL ENGINE SPEED CONTROL SYSTEM
Unique features for the 2.5L diesel engine will be
covered in this section.
• Models equipped with the 2.5L diesel engine do
not use a vacuum reservoir to retain engine vacuum
for speed control operation. There are no vaccum-op-
erated speed control servos used in vehicles with the
2.5L diesel engine.
• The range of the speed control system operation
is restricted to speeds between 56 km/h (35 MPH) to
145 km/h (90 MPH).
• Inputs to the MSA that allow speed control oper-
ation are from the vehicle speed sensor and the
Speed Control Switch.
• Two separate speed control switch modules are
mounted on the steering wheel to the left and right
side of the driver's airbag module. Switch features
are:
• Within the two switch modules, five momen-
tary contact switches, supporting seven different
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speed control functions are used. The outputs from
these switches are filtered into one input. The MSA
determines which output has been applied through
resistive multiplexing. The input circuit voltage is
measured by the MSA to determine which switch
function has been selected.
• A speed control indicator lamp, located on the
instrument panel cluster is energized by the MSA via
the CCD Bus. This occurs when speed control system
power has been turned ON, and the engine is run-
ning.
• The two switch modules are labeled: ON/OFF,
SET, RESUME/ACCEL, CANCEL and COAST. Refer
to the owner's manual for more information on speed
control switch functions and setting procedures. The
individual switches cannot be repaired. If one indi-
vidual switch fails, the switch module must be
replaced.
VEHICLE SPEED CONTROL SYSTEM 8H - 1