Dodge Dakota Sport 2001 Service Manual page 556

AN
SERVO (Continued)
Fig. 5 Speed Control Cable at Bracket—4.7L V-8
1 - PLASTIC CABLE MOUNT
2 - SPEED CONTROL CABLE
3 - BRACKET
4 - SLIDE FOR REMOVAL
OPERATION
The Powertrain Control Module (PCM) controls the
solenoid valve body. The solenoid valve body controls
the application and release of vacuum to the dia-
phragm of the vacuum servo. The servo unit cannot
be repaired and is serviced only as a complete assem-
bly.
Power is supplied to the servo's by the PCM
through the brake switch. The PCM controls the
ground path for the vacuum and vent solenoids.
The dump solenoid is energized anytime it receives
power. If power to the dump solenoid is interrupted,
the solenoid dumps vacuum in the servo. This pro-
vides a safety backup to the vent and vacuum sole-
noids.
The vacuum and vent solenoids must be grounded
at the PCM to operate. When the PCM grounds the
vacuum servo solenoid, the solenoid allows vacuum
to enter the servo and pull open the throttle plate
using the cable. When the PCM breaks the ground,
the solenoid closes and no more vacuum is allowed to
enter the servo. The PCM also operates the vent sole-
noid via ground. The vent solenoid opens and closes a
passage to bleed or hold vacuum in the servo as
required.
Engine
The PCM duty cycles the vacuum and vent sole-
noids to maintain the set speed, or to accelerate and
decelerate the vehicle. To increase throttle opening,
the PCM grounds the vacuum and vent solenoids. To
decrease throttle opening, the PCM removes the
grounds from the vacuum and vent solenoids. When
the brake is released, if vehicle speed exceeds 30
mph to resume, 35 mph to set, and the RES/ACCEL
switch has been depressed, ground for the vent and
vacuum circuits is restored.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Disconnect vacuum hose (line) at servo (Fig. 6).
(3) Disconnect electrical connector at servo.
(4) Disconnect servo cable at throttle body. Refer to
Servo Cable Removal/Installation.
(5) Remove 2 mounting nuts holding servo cable
sleeve to bracket (Fig. 6) or (Fig. 7).
(6) Pull speed control cable sleeve and servo away
from servo mounting bracket to expose cable retain-
ing clip (Fig. 7) and remove clip. Note: The servo
mounting bracket displayed in (Fig. 7) is a typical
bracket and may/may not be applicable to this model
vehicle.
Fig. 6 Speed Control Servo Location
1 - SPEED CONTROL SERVO
2 - VACUUM HOSE
3 - SERVO BRACKET NUTS (2)
4 - SERVO CABLE
5 - CABLE SLEEVE
6 - SERVO MOUNTING NUTS (2)
7 - ELECTRICAL CONNECTOR
(7) Remove servo from mounting bracket. While
removing, note orientation of servo to bracket.
SPEED CONTROL 8P - 5