engine DODGE RAM 2002 Service Repair Manual

SPEED CONTROL
TABLE OF CONTENTS
page page
SPEED CONTROL
DESCRIPTION
DESCRIPTION - SPEED CONTROL SYSTEM . 1
DESCRIPTION - VEHICLE SPEED INPUT....2
OPERATION - SPEED CONTROL SYSTEM....2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VACUUM
SUPPLY TEST.........................3
DIAGNOSIS AND TESTING - ROAD TEST....4
SPECIFICATIONS
TORQUE - SPEED CONTROL SYSTEM.....4
CABLE
DESCRIPTION..........................4
OPERATION............................4
REMOVAL
REMOVAL - GAS ENGINES...............4
REMOVAL - DIESEL WITH AUTO. TRANS. . . . 5
INSTALLATION
INSTALLATION - GAS ENGINES...........5
INSTALLATION - DIESEL WITH AUTO.
TRANS...............................6SPEED CONTROL SERVO
DESCRIPTION..........................6
OPERATION............................6
REMOVAL
REMOVAL............................6
REMOVAL - DIESEL WITH AUTO. TRANS. . . . 9
INSTALLATION
INSTALLATION.......................11
INSTALLATION - DIESEL WITH AUTO.
TRANS..............................12
SWITCH
DESCRIPTION.........................12
OPERATION...........................12
REMOVAL.............................13
INSTALLATION.........................14
VACUUM RESERVOIR
DESCRIPTION.........................14
REMOVAL.............................14
INSTALLATION.........................15
SPEED CONTROL
DESCRIPTION
DESCRIPTION - SPEED CONTROL SYSTEM
Gas Engines and/or Diesel With Automatic Trans.
The speed control system is operated by the use of
a cable and a vacuum controlled servo. Electronic
control of the speed control system is integrated into
the Powertrain Control Module (PCM). The controls
consist of two steering wheel mounted switches. The
switches are labeled: ON/OFF, RES/ACCEL, SET,
COAST, and CANCEL.
The system is designed to operate at speeds above
30 mph (50 km/h).
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THATARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
Diesel With Manual Trans.
The speed control system is fully electronically con-
trolled by the Engine Control Module (ECM).A
cable and a vacuum controlled servo are not
used if the vehicle is equipped with a manual
transmission and a diesel engine. This is a ser-
vo-less system.The controls consist of two steering
wheel mounted switches. The switches are labeled:
ON/OFF, RES/ACCEL, SET, COAST, and CANCEL.
The system is designed to operate at speeds above
30 mph (50 km/h).
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
BR/BESPEED CONTROL 8P - 1

DESCRIPTION - VEHICLE SPEED INPUT
Gas Engines and/or Diesel With Automatic Trans.
The Vehicle Speed Sensor (VSS) is no longer used
for any Dodge Truck.
Vehicle speed and distance covered are measured
by the Rear Wheel Speed Sensor. The sensor is
mounted to the rear axle. A signal is sent from this
sensor to the Controller Antilock Brake (CAB) com-
puter. A signal is then sent from the CAB to the Pow-
ertrain Control Module (PCM) to determine vehicle
speed and distance covered. The PCM will then
determine strategies for speed control system opera-
tion.
Diesel With Manual Trans.
The Vehicle Speed Sensor (VSS) is no longer used
for any Dodge Truck.
Vehicle speed and distance covered are measured
by the Rear Wheel Speed Sensor. The sensor is
mounted to the rear axle. A signal is sent from this
sensor to the Controller Antilock Brake (CAB) com-
puter. A signal is then sent from the CAB to the
Engine Control Module (ECM) to determine vehicle
speed and distance covered. The ECM will then
determine strategies for speed control system opera-
tion.
OPERATION - SPEED CONTROL SYSTEM
Gas Engines and/or Diesel With Automatic Trans.
When speed control is selected by depressing the
ON switch, the PCM allows a set speed to be stored
in PCM RAM for speed control. To store a set speed,
depress the SET switch while the vehicle is moving
at a speed between 35 and 85 mph. In order for the
speed control to engage, the brakes cannot be
applied, nor can the gear selector be indicating the
transmission is in Park or Neutral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal.
²Depressing the OFF switch.
²Depressing the CANCEL switch.
²Depressing the clutch pedal (if equipped).
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the PCM.
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²An indication of Park or Neutral.
²A rapid increase of rpm (indication that the
clutch has been disengaged).²Excessive engine rpm (indicates that the trans-
mission may be in a low gear).
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low).
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate).
Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the PCM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
PCM when the RES/ACCEL is released. The PCM
also has a9tap-up9feature in which vehicle speed
increases at a rate of approximately 2 mph for each
momentary switch activation of the RES/ACCEL
switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
Diesel With Manual Trans.
When speed control is selected by depressing the
ON switch, the Engine Control Module (ECM) allows
a set speed to be stored in ECM RAM for speed con-
trol. To store a set speed, depress the SET switch
while the vehicle is moving at a speed between 35
and 85 mph. In order for the speed control to engage,
the brakes cannot be applied.The speed control can
be disengaged manually by:
²Stepping on the brake pedal.
²Depressing the OFF switch.
²Depressing the CANCEL switch.
²Depressing the clutch pedal.
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the ECM.
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²A rapid increase of rpm (indication that the
clutch has been disengaged).
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear).
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low).
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate).
8P - 2 SPEED CONTROLBR/BE
SPEED CONTROL (Continued)

Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the ECM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
ECM when the RES/ACCEL is released. The ECM
also has a9tap-up9feature in which vehicle speed
increases at a rate of approximately 2 mph for each
momentary switch activation of the RES/ACCEL
switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VACUUM SUPPLY
TEST
Gas Powered Engines
On gasoline powered engines: actual engine vac-
uum, a vacuum reservoir, a one-way check valve and
vacuum lines are used to supply vacuum to the speed
control servo.
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
(5) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoirand engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
Diesel Engines With Automatic Trans.
On diesel powered engines equipped with an auto-
matic transmission: an engine driven vacuum pump,
a one-way check valve and vacuum lines are used to
supply vacuum to the speed control servo. A vacuum
reservoir is not used.
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. For
vacuum testing and vacuum specifications, refer to
Vacuum Pump OutputÐDiesel Engine in 9, Engines.
(3) If vacuum pump output is OK, determine other
source of leak. Check all vacuum lines to: speed con-
trol servo, engine vacuum pump and heating/air con-
ditioning system for leaks.
(4) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between speed control servo
and engine vacuum pump. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
Diesel Engine With Manual Trans.
Vacuum is not used for any part of the speed con-
trol system if equipped with a diesel engine and a
manual transmission.
BR/BESPEED CONTROL 8P - 3
SPEED CONTROL (Continued)

DIAGNOSIS AND TESTING - ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer.
If a road test verifies a system problem and the
speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose, damaged or corroded electrical connec-
tions at the servo. Corrosion should be removed from
electrical terminals and a light coating of Mopart
MultiPurpose Grease, or equivalent, applied.²Leaking vacuum reservoir.
²Loose or leaking vacuum hoses or connections.
²Defective one-way vacuum check valve.
²Secure attachment of both ends of the speed con-
trol servo cable.
²Smooth operation of throttle linkage and throttle
body air valve.
²Failed speed control servo. Do the servo vacuum
test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
SPECIFICATIONS
TORQUE - SPEED CONTROL SYSTEM
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Servo Mounting Bracket
Nuts8.5 - 75
Switch Module Mounting
Screws3-26
Vacuum Reservoir
Mounting Screws2.2 -
20
CABLE
DESCRIPTION
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage.
OPERATION
This cable causes the throttle control linkage to
open or close the throttle valve in response to move-
ment of the vacuum servo diaphragm.
REMOVAL
REMOVAL - GAS ENGINES
(1) Disconnect negative battery cable at battery.
(2) Remove air cleaner (all except 8.0L V-10
engine).(3) Using finger pressure only, remove speed con-
trol cable connector at bellcrank by pushing connec-
tor off the bellcrank pin (Fig. 1) or (Fig. 2).DO NOT
try to pull connector off perpendicular to the
bellcrank pin. Connector will be broken.Fig. 1 Servo Cable at Throttle BodyÐV6/V-8 Engine
1 - VEHICLE SPEED CONTROL CABLE
8P - 4 SPEED CONTROLBR/BE
SPEED CONTROL (Continued)

(4) Squeeze 2 tabs on sides of speed control cable
at throttle body mounting bracket (locking plate) and
push out of bracket.
(5) Remove servo cable from servo. Refer to Speed
Control Servo Removal/Installation in this group.
REMOVAL - DIESEL WITH AUTO. TRANS.
(1) Disconnect both negative battery cables at both
batteries.
(2) Remove cable/lever/linkage cover. Refer to
Speed Control Servo Removal/Installation.
(3) Remove (disconnect) servo cable from servo.
Refer to Speed Control Servo Removal/Installation.
(4) Using finger pressure only, disconnect end of
servo cable from throttle lever pin by pulling forward
on connector while holding lever rearward (Fig. 3).
DO NOT try to pull connector off perpendicular
to lever pin. Connector will be broken.(5) Squeeze 2 pinch tabs (Fig. 3) on sides of speed
control cable at mounting bracket and push cable
rearward out of bracket.
(6) Remove cable from vehicle.
INSTALLATION
INSTALLATION - GAS ENGINES
(1) Install end of cable to speed control servo.
Refer to Speed Control Servo Removal/Installation.
(2) Install cable into throttle body mounting
bracket. Cable snaps into bracket.
(3) Install speed control cable connector at throttle
body bellcrank pin. Connector snaps onto pin.
(4) Connect negative battery cable to battery.
(5) Before starting engine, operate accelerator
pedal to check for any binding.
Fig. 2 Servo Cable at Throttle BodyÐV-10 Engine
1 - THROTTLE CABLE
2 - THROTTLE VALVE CABLE3 - SPEED CONTROL SERVO CABLE
BR/BESPEED CONTROL 8P - 5
CABLE (Continued)

INSTALLATION - DIESEL WITH AUTO. TRANS.
(1) Install (connect) end of speed control servo
cable to speed control servo. Refer to Speed Control
Servo Removal/Installation.
(2) Install cable through mounting hole on mount-
ing bracket. Cable snaps into bracket.
(3) Connect servo cable to throttle lever by push-
ing cable connector rearward onto lever pin while
holding lever forward.
(4) Connect negative battery cables to both batter-
ies.
(5) Before starting engine, operate accelerator
pedal to check for any binding.
(6) Install cable/lever cover.
SPEED CONTROL SERVO
DESCRIPTION
A speed control servo is not used if equipped
with both a diesel engine and a manual trans-
mission.
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The solenoid valve body con-
tains three solenoids:
²Vacuum²Vent
²Dump
The vacuum chamber contains a diaphragm with a
cable attached to control the throttle linkage.
OPERATION
A speed control servo is not used if equipped
with both a diesel engine and a manual trans-
mission.
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.
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
REMOVAL
V-8 ENGINE
(1) Disconnect negative battery cable at battery.
(2) Disconnect electrical connector at servo (Fig. 4).
(3) Disconnect vacuum hose at servo.
(4) Disconnect servo cable at throttle body. Refer to
Servo Cable Removal/Installation in this group.
Fig. 3 Servo Cable at Throttle Lever
1 - PINCH (2) TABS
2 - CABLE MOUNTING BRACKET
3 - PINCH TABS (2)
4 - OFF
5 - THROTTLE CABLE
6 - THROTTLE LEVER
7 - THROTTLE LEVER PIN
8 - OFF
9 - CONNECTOR
10 - SPEED CONTROL CABLE
8P - 6 SPEED CONTROLBR/BE
CABLE (Continued)

8.0L V-10 ENGINE
(1) Disconnect negative battery cable at battery.
(2) Disconnect positive battery cable at battery.
(3) Remove 2 bolts and battery holddown (Fig. 7).
(4) If equipped, pull up on battery heat shield to
remove it (Fig. 8).
(5) Remove battery from vehicle.
(6) From under left front wheel opening, remove 2
forward battery tray nuts (Fig. 9).(7) Remove 2 nuts and 2 bolts holding battery tray
to vehicle (Fig. 10).
Fig. 7 Battery Holddown
1 - REMOVE 2 BOLTS
2 - BATTERY HOLDDOWN STRAP
Fig. 8 Battery Heat Shield
1 - BATTERY HEAT SHIELD
Fig. 9 Forward Battery Tray Nuts
1 - HORNS
2 - UNDERSIDE OF LEFT FRONT WHEEL OPENING
3 - BATTERY TRAY NUTS
Fig. 10 Battery Tray Mounting
1 - BATTERY TRAY
2 - REMOVE 2 BOLTS
3 - REMOVE 2 NUTS
8P - 8 SPEED CONTROLBR/BE
SPEED CONTROL SERVO (Continued)

INSTALLATION
INSTALLATION
V-8 ENGINE
(1) Position servo to mounting bracket.
(2) Align hole in cable connector with hole in servo
pin. Install cable-to-servo retaining clip.
(3) Insert servo studs through holes in servo
mounting bracket.
(4) Insert servo studs through holes in servo cable
sleeve.
(5) Install servo mounting nuts and tighten to 8.5
N´m (75 in. lbs.) torque.
(6) Connect vacuum line to servo.
(7) Connect electrical connector to servo terminals.
(8) Install three bolts retaining servo/servo mount-
ing bracket to battery tray.
(9) Connect servo cable to throttle body. Refer to
Servo Cable Removal/Installation in this group.
(10) Connect negative battery cable to battery.
(11) Before starting engine, operate accelerator
pedal to check for any binding.
8.0L V-10 ENGINE
(1) Position servo to mounting bracket.
(2) Align hole in cable connector with hole in servo
pin. Install cable-to-servo retaining clip.
(3) Insert servo studs through holes in servo
mounting bracket.
Fig. 17 Servo LocationÐRemoval/Installation
1 - BATTERY TRAY
2 - SERVO ELECTRICAL CONNECTOR
3 - SERVO BRACKET SCREWS (3)
Fig. 18 Servo Mounting at Battery Tray
1 - BATTERY TRAY
2 - SPEED CONTROL SERVO
3 - SERVO MOUNTING NUTS (2)
Fig. 19 Servo Cable Clip Remove/InstallÐTypical
1 - SERVO MOUNTING NUTS (2)
2 - SERVO
3 - CABLE RETAINING CLIP
4 - SERVO CABLE AND SLEEVE
BR/BESPEED CONTROL 8P - 11
SPEED CONTROL SERVO (Continued)

(4) Insert servo studs through holes in servo cable
sleeve.
(5) Install servo mounting nuts and tighten to 8.5
N´m (75 in. lbs.) torque.
(6) Connect vacuum line to servo.
(7) Connect electrical connector to servo terminals.
(8) Connect servo cable to throttle body. Refer to
Servo Cable Removal/Installation in this group.
(9) Install battery tray. Tighten all battery tray
mounting hardware to 16 N´m (140 in. lbs.) torque.
(10) Position battery into battery tray.
(11) If equipped, install battery heat shield.
(12) Install battery holddown clamp. Tighten bolt
to 4 N´m (35 in. lbs.) torque.
(13) Connect positive battery cable to battery.
(14) Connect negative battery cable to battery.
(15) Before starting engine, operate accelerator
pedal to check for any binding.
INSTALLATION - DIESEL WITH AUTO. TRANS.
(1) Position servo to mounting bracket.
(2) Align hole in cable connector with hole in servo
pin. Install cable-to-servo retaining clip.
(3) Insert servo studs through holes in servo
mounting bracket.
(4) Insert servo studs through holes in servo cable
sleeve.
(5) Install servo mounting nuts and tighten to 8.5
N´m (75 in. lbs.) torque.
(6) Connect vacuum line to servo.
(7) Connect electrical connector to servo terminals.
(8) Connect servo cable to throttle lever by push-
ing cable connector rearward onto lever pin while
holding lever forward.
(9) Install battery tray. Tighten all battery tray
mounting hardware to 16 N´m (140 in. lbs.) torque.
(10) Position battery into battery tray.
(11) If equipped, install battery heat shield.
(12) Install battery holddown clamp. Tighten bolt
to 4 N´m (35 in. lbs.) torque.
(13) Connect positive battery cable to battery.
(14) Connect negative battery cables to both bat-
teries.
(15) Before starting engine, operate accelerator
pedal to check for any binding.
(16) Install cable/lever cover.
SWITCH
DESCRIPTION
Gas Engines and Diesel With Auto. Trans.
There are two separate switch pods that operate
the speed control system. The steering-wheel-
mounted switches use multiplexed circuits to provideinputs to the Powertrain Control Module (PCM) for
ON, OFF, RESUME, ACCELERATE, SET, DECEL
and CANCEL modes. 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
switch fails, the entire switch module must be
replaced.
Diesel With Manual Trans.
There are two separate switch pods that operate
the speed control system. The steering-wheel-
mounted switches use multiplexed circuits to provide
inputs to the Engine Control Module (ECM) for ON,
OFF, RESUME, ACCELERATE, SET, DECEL and
CANCEL modes. 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
switch fails, the entire switch module must be
replaced.
OPERATION
Gas Engines and Diesel With Auto. Trans.
When speed control is selected by depressing the
ON, OFF switch, the Powertrain Control Module
(PCM) allows a set speed to be stored in its RAM for
speed control. To store a set speed, depress the SET
switch while the vehicle is moving at a speed
between approximately 35 and 85 mph. In order for
the speed control to engage, the brakes cannot be
applied, nor can the gear selector be indicating the
transmission is in Park or Neutral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal.
²Depressing the OFF switch.
²Depressing the CANCEL switch.
The speed control can be disengaged also by any of
the following conditions:
²An indication of Park or Neutral.
²The vehicle speed signal increases at a rate of
10 mph per second (indicates that the co-efficient of
friction between the road surface and tires is
extremely low).
²Depressing the clutch pedal.
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear).
²The vehicle speed signal decreases at a rate of
10 mph per second (indicates that the vehicle may
have decelerated at an extremely high rate).
²If the actual speed is not within 20 mph of the
set speed.
The previous disengagement conditions are pro-
grammed for added safety.
8P - 12 SPEED CONTROLBR/BE
SPEED CONTROL SERVO (Continued)

Once the speed control has been disengaged,
depressing the ACCEL switch restores the vehicle to
the target speed that was stored in the PCM's RAM.
NOTE: Depressing the OFF switch will erase the set
speed stored in the PCM's RAM.
If, while the speed control is engaged, the driver
wishes to increase vehicle speed, the PCM is pro-
grammed for an acceleration feature. With the
ACCEL switch held closed, the vehicle accelerates
slowly to the desired speed. The new target speed is
stored in the PCM's RAM when the ACCEL switch is
released. The PCM also has a9tap-up9feature in
which vehicle speed increases at a rate of approxi-
mately 2 mph for each momentary switch activation
of the ACCEL switch.
The PCM also provides a means to decelerate with-
out disengaging speed control. To decelerate from an
existing recorded target speed, depress and hold the
COAST switch until the desired speed is reached.
Then release the switch. The ON, OFF switch oper-
ates two components: the PCM's ON, OFF input, and
the battery voltage to the brake switch, which powers
the speed control servo.
Diesel With Manual Trans.
When speed control is selected by depressing the
ON, OFF switch, the Engine Control Module (ECM)
allows a set speed to be stored in its RAM for speed
control. To store a set speed, depress the SET switch
while the vehicle is moving at a speed between
approximately 35 and 85 mph. In order for the speed
control to engage, the brakes cannot be applied.
The speed control can be disengaged manually by:
²Stepping on the brake pedal.
²Depressing the OFF switch.
²Depressing the CANCEL switch.
The speed control can be disengaged also by any of
the following conditions:
²The vehicle speed signal increases at a rate of
10 mph per second (indicates that the co-efficient of
friction between the road surface and tires is
extremely low).
²Depressing the clutch pedal.
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear).
²The vehicle speed signal decreases at a rate of
10 mph per second (indicates that the vehicle may
have decelerated at an extremely high rate).
²If the actual speed is not within 20 mph of the
set speed.The previous disengagement conditions are pro-
grammed for added safety.
Once the speed control has been disengaged,
depressing the ACCEL switch restores the vehicle to
the target speed that was stored in the ECM's RAM.
NOTE: Depressing the OFF switch will erase the set
speed stored in the ECM's RAM.
If, while the speed control is engaged, the driver
wishes to increase vehicle speed, the ECM is pro-
grammed for an acceleration feature. With the
ACCEL switch held closed, the vehicle accelerates
slowly to the desired speed. The new target speed is
stored in the ECM's RAM when the ACCEL switch is
released. The ECM also has a9tap-up9feature in
which vehicle speed increases at a rate of approxi-
mately 2 mph for each momentary switch activation
of the ACCEL switch.
The ECM also provides a means to decelerate with-
out disengaging speed control. To decelerate from an
existing recorded target speed, depress and hold the
COAST switch until the desired speed is reached.
Then release the switch. The ON, OFF switch oper-
ates two components: the ECM's ON, OFF input, and
the battery voltage to the brake switch, which powers
the speed control servo.
REMOVAL
WARNING: BEFORE BEGINNING ANY AIRBAG SYS-
TEM COMPONENT REMOVAL OR INSTALLATION,
REMOVE AND ISOLATE THE NEGATIVE (-)
CABLE(S) FROM THE BATTERY. THIS IS THE ONLY
SURE WAY TO DISABLE THE AIRBAG SYSTEM.
THEN WAIT TWO MINUTES FOR SYSTEM CAPACI-
TOR TO DISCHARGE BEFORE FURTHER SYSTEM
SERVICE. FAILURE TO DO THIS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE INJURY.
(1) Disconnect and isolate negative battery
cable(s).
(2) Remove airbag module. Refer to 8, Restraint
Systems for procedures.
(3) Remove switch-to-steering wheel mounting
screws (Fig. 20).
(4) Remove switch.
(5) Remove electrical connector at switch.
BR/BESPEED CONTROL 8P - 13
SWITCH (Continued)