2002 DODGE RAM ESP

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

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)

(5) Remove three bolts retaining servo/servo
mounting bracket to side of battery tray (Fig. 5).
(6) Position servo assembly to gain access to 2
servo mounting nuts (Fig. 5) or (Fig. 6).
(7) Remove 2 mounting nuts holding servo cable
sleeve to bracket (Fig. 6).
(8) Pull speed control cable sleeve and servo away
from servo mounting bracket to expose cable retain-
ing clip (Fig. 6) and remove clip. Note: The servo
mounting bracket displayed in (Fig. 6) is a typical
bracket and may/may not be applicable to this model
vehicle.
(9) Remove servo from mounting bracket. While
removing, note orientation of servo to bracket.
Fig. 4 Servo LocationÐRemoval/Installation
1 - BATTERY TRAY
2 - SERVO ELECTRICAL CONNECTOR
3 - SERVO BRACKET SCREWS (3)
Fig. 5 Servo Mounting at Battery Tray
1 - BATTERY TRAY
2 - SPEED CONTROL SERVO
3 - SERVO MOUNTING NUTS (2)
Fig. 6 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 - 7
SPEED CONTROL SERVO (Continued)

(8) Disconnect servo cable at throttle body. Refer to
Servo Cable Removal/Installation in this group.
(9) Position battery tray up far enough for access
to speed control servo electrical connector and vac-
uum line.
(10) Disconnect electrical connector and vacuum
line at servo.
(11) Position battery tray with attached servo
assembly to gain access to 2 servo mounting nuts
(Fig. 5) or (Fig. 6).
(12) Remove 2 mounting nuts holding servo cable
sleeve to bracket (Fig. 6).
(13) Pull speed control cable sleeve and servo away
from servo mounting bracket to expose cable retain-
ing clip (Fig. 6) and remove clip. Note: The servo
mounting bracket displayed in (Fig. 6) is a typical
bracket and may/may not be applicable to this model
vehicle.
(14) Remove servo from mounting bracket. While
removing, note orientation of servo to bracket.
REMOVAL - DIESEL WITH AUTO. TRANS.
(1) Disconnect both negative battery cables at both
batteries.
(2) Disconnect positive battery cable at battery
(drivers side battery).
(3) Remove battery holddown bolts (Fig. 11).
(4) If equipped, pull up on battery heat shield to
remove it (Fig. 12).
(5) Remove battery from vehicle.
(6) From under vehicle, and in front of left front
wheelhouse, remove 2 lower battery tray nuts (Fig.
13).
(7) Remove 2 nuts and 2 bolts holding battery tray
to vehicle (Fig. 14).
(8) Remove cable cover (Fig. 15). Cable cover is
attached with 2 Phillips screws, 2 plastic retention
clips and 2 push tabs (Fig. 15). Remove 2 Phillips
screws and carefully pry out 2 retention clips. After
clip removal, push rearward on front tab, and
upward on lower tab for cover removal.
(9) Using finger pressure only, disconnect end of
servo cable from throttle lever pin by pulling forward
on connector while holding lever rearward (Fig. 16).
DO NOT try to pull connector off perpendicular
to lever pin. Connector will be broken.
Fig. 11 Battery Holddown Bolts
1 - REMOVE 2 BOLTS
2 - BATTERY HOLDDOWN STRAP
Fig. 12 Battery Heat Shield
1 - BATTERY HEAT SHIELD
Fig. 13 Battery Tray Lower Mounting Nuts
1 - BATTERY TRAY
2 - SPEED CONTROL SERVO
BR/BESPEED CONTROL 8P - 9
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)

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)