System Description
Caution: Do not use the cruise control on slippery roads, steeply graded roads,
or in heavy traffic of heavy or varying volume. Failure to follow these CAUTIONS
could possibly cause you to loose control of the vehicle and result in damage
to the vehicle and personal injury.
Cruise control is a speed control system that maintains
a desired vehicle speed under normal driving conditions. However, steep grades
up or down may cause variations in the selected speeds. The cruise control
system has the capability to perform the following actions:
The cruise control circuit contains the following components:
• | A Cruise Control Module |
• | A Cruise Control Switch |
• | The Vehicle Speed Sensor (VSS) |
The cruise control module and the servo are the two main components
that allow the system to control and maintain the desired vehicle speed. The
cruise control module monitors vehicle speed and provides the cruise control
servo with the necessary commands to maintain or change vehicle speed
in response to inputs from the cruise control switch. In response to the
control module, the servo moves a connecting arm. The connecting arm is
attached to the cruise control cable. The cable moves the throttle linkage
in order to vary the throttle position. This action maintains the desired
cruise speed. The cruise control module contains a low speed limit that
will prevent system engagement below a minimum speed of approximately 40.23 km/h
(25 mph). The module is controlled by the cruise control switch.
The cruise control is in "Standby Disabled" until all of the
conditions that are inconsistent with the cruise control operation are
cleared.
Cruise control operation is disengaged when the cruise control module
receives a cancel signal from the following components:
• | The Cruise Control Switch |
• | The Park/Neutral Position (PNP) Switch on vehicles equipped with
an auto transaxle |
• | The Cruise Control Release Switch on vehicles equipped with an
manual transaxle |
Upon receiving a cancel signal, the cruise control de-energizes the
magnetic clutch inside the cruise control servo. With the magnetic clutch
de-energized, the servo and the connecting arm are no longer mechanically
connected and the throttle returns to the idle position.
Servo Description
The servo (1) is mounted
to the right strut tower and consists of a DC servo motor, a worm gear, a
throttle angle sensor (potentiometer) and a magnetic clutch. Acting
in response to signals from the cruise control module, the servo's
DC servo motor actuates the accelerator cable to increase and decrease
throttle angle.
Cruise Control Module Description
The cruise control module (2) is located to the right of the instrument
panel compartment. The main function of the cruise control module is to monitor
and act upon input signals from the cruise control switch and the
Vehicle Speed Sensor (VSS).
There are four different categories of input signals received by the
cruise control module. These four categories are ON/OFF, speed control, throttle
position and cancel. The ON/OFF input signal to the cruise control
module is provided by the cruise control switch and simply activates
and de-activates the cruise control system. The speed control
input signals to the cruise module are provided by the cruise control
switch and the VSS. Speed control input signals are provided by the
cruise control switch are the RES/ACC (Resume/Accelerate) signal
and the SET/COAST signal. These signals are also used to initiate
the tap-up and tap-down functions. The cruise control module uses
these signals, in addition to the vehicle speed signal from the VSS,
to determine and maintain or alter vehicle speed in accordance with
the driver's commands. The throttle position signals to the cruise
control module are provided by the servo and the idle switch inside
the Throttle Position (TP) sensor. These signals, as their names
suggest, allow the cruise control module to constantly monitor throttle
position during cruise control system operation. The cancel input
signals to the cruise control module are provided by the cruise control
switch CANCEL signal, the stoplamp switch, the PNP switch, or the
cruise control release switch. These input signals inform the cruise
control module that cruise control operation should be immediately
suspended.
Output signals from the cruise control module are all sent to the cruise
control servo and will vary depending upon the type of input signals received.
If, for example, the cruise control module senses that vehicle speed
has dropped below the desired cruise speed, an output signal will
be sent to the OPEN side of the DC servo motor within the cruise
control servo. This action will cause the motor to turn the worm
gear, open the throttle, and increase vehicle speed until the desired
cruise speed is activated. If the cruise control module should sense
that vehicle speed is above the desired cruise speed, an output signal
is sent to the CLOSE side of the DC servo motor within the cruise
control servo. This action will cause the motor to turn in the opposite
direction, close the throttle, and decrease vehicle speed until the
desired cruise speed is achieved. Finally, should a cancel input
signal be received, the cruise control module de-energizes the magnetic
clutch within the servo. This action disengages the DC servo motor
from the worm gear, causing the throttle to go to the idle position
and effectively canceling cruise control operation.
The cruise control module also has a self-diagnostic capability. In
conjunction with the cruise control switch, it can be used to run an abbreviated
self-test which covers all cruise control switch positions, the stoplamp
switch, the PNP switch, the cruise control release switch, and the
VSS. In addition to the abbreviated self-test, grounding the Tc terminal
in the Data Link Connector (DLC) allows the cruise control module
to flash Diagnostic Trouble Codes (DTCs) on the CRUISE indicator.
By reading the DTCs and following the diagnostic tables, any electrical
problem in the cruise control system can be identified and repaired.
RES/ACC Switch
The RES/ACC (Resume/Accelerate)
switch returns cruise control system operation to the last speed setting after
a cancel input signal is received by the cruise control module (such
as vehicle braking). This switch is activated when the cruise control
switch is momentarily moved upward. Do not hold the cruise control
switch in this position. Release it immediately. If the cruise control
switch is held in the RES/ACC position for more than one second,
the system goes into the accelerate mode. If acceleration during
cruise control system operation is desired, move the cruise control
switch upward into the RES/ACC position and hold it there until
the vehicle reaches the desired speed. When the cruise control switch
is released, the cruise control system will maintain the new cruise
speed. In order to use the accelerate mode, the cruise on-off switch
button must have been pressed, the CRUISE indicator must be lit,
and the vehicle speed must be over 40 km/h (25 mph).
SET/COAST Switch
The SET/COAST switch is
activated when the cruise control switch is moved downward into the SET/COAST
position. When the cruise control switch is moved downward into the
SET/COAST position and released, the cruise speed will be set at
the speed at which the vehicle was traveling when the switch was
activated. In order for this switch to operate, however, the cruise
on-off switch button must have been pressed, the CRUISE indicator
must be lit, and the vehicle speed must be over 40 km/h (25 mph).
The SET/COAST switch can also be used to decrease the cruise speed.
By moving the cruise control switch downward into the SET/COAST position and
holding it there, the cruise control system will disengage and allow
the throttle to return to the idle position. When the new, lower
cruise speed has been reached, the cruise control switch is released
from the SET/COAST position. Once released, the cruise control system
will re-engage and maintain the new desired cruise speed.
The SET/COAST switch can also be used to tap-down vehicle speed. In
order to do this, the cruise control system must be engaged and operating.
Tapping-down is performed by quickly moving the cruise control switch
down into the SET/COAST position and releasing it (or tapping the
switch into the SET/COAST position). Do not hold the cruise control
switch in the SET/Coast position, or the cruise control system will
enter the coast mode. Tap-down is a function in which cruise speed
can be decreased by 1.6 km/h (1 mph) increments) (one
tap = 1.6 km/h [1 mph] decrease).
The accelerator may be pressed at any time to override cruise control
system operation. Release of the accelerator will return the vehicle to the
previously set cruise speed.
Vehicle Speed Sensor Description
The VSS is an electronic relay that is mounted on the transaxle. As
the transaxle turns the VSS, the VSS provides the speedometer with a vehicle
speed input (voltage pulses). This input is used to drive the speedometer.
The speedometer then converts the Vehicle speed input into a more
precise waveform and provides the Powertrain Control Module (PCM)
and the cruise control module with its own vehicle speed input. The
cruise control module converts this input into a vehicle speed. For
vehicle speed sensor replacement procedures, refer to
Vehicle Speed Sensor Replacement
in Automatic
Transmission - 3 Speed,
Vehicle Speed Sensor Replacement
in Automatic Transmission - 4 Speed or
Vehicle Speed Sensor Replacement
in Manual
Transmission - MB4 and MB5.
The RES/ACC switch can also be used to tap-up vehicle speed. In order
to do this, the cruise control system must be engaged and operating. Tapping-up
is performed by quickly moving the cruise control switch up into
the RES/ACC position and releasing it (or tapping the switch into
the RES/ACC position). Do not hold the cruise control switch in the
RES/ACC position, or the cruise control system will enter the accelerate
mode. Tap-up is a function in which cruise speed can be increased
by 1.6 km/h (1 mph) increments (one tap = 1.6 km/h
[1 mph] increase).
Stoplamp Switch Description
The stoplamp switch is located under the instrument panel directly above
the brake pedal. Whenever the brake pedal is pressed, one set of stoplamp
switch contacts close and a voltage signal is provided to the cruise
control module. The cruise control module disengages cruise control
system operation as soon as this voltage signal is sensed.
When the brake pedal is pressed, another set of stoplamp switch contacts
open, and the voltage circuit from the cruise control module to the magnetic
clutch inside the servo is interrupted. With voltage removed from
the magnetic clutch, the servos DC servo motor is disengaged from
the worm gear and the throttle is permitted to return to the idle
position. This feature is provided to ensure the cancellation of
cruise control system operation during vehicle braking. For stoplamp
switch replacement and adjustment procedures, refer to
Stop Lamp Switch Replacement
in Hydraulic Brakes.
Clutch Control Release Switch Description
The cruise control release switch is mounted under the instrument panel
directly above the clutch pedal. Whenever the clutch pedal is pressed, the
cruise control release switch closes and provides a ground to the
cruise control module. The cruise control module disengages cruise
control system operation as soon as this ground signal is sensed.
Park/Neutral Position (PNP) Switch Description
The PNP switch (2) is
mounted to the transaxle. Whenever the manual selector lever is placed in
either the Park (P) or Neutral (N) position, the PNP switch closes
and provides a ground to the cruise control module. The cruise
control module disengages cruise control system operation as soon
as this ground signal is sensed. For PNP switch replacement and adjustment
procedures, refer to
Park/Neutral Position Switch
in Automatic Transaxle - 4 speed or
Park/Neutral Position Switch Replacement
in Automatic Transaxle
- 3 speed.
Cruise On-Off Switch
The cruise on-off switch
is a momentary contact type button located on the end of the cruise control
switch. The purpose of the cruise on-off switch is to turn the
cruise control system ON and OFF.
Cruise Indicator Description
The CRUISE indicator, located in the instrument cluster assembly, turns
ON to inform the driver that the cruise control system is operational. The
CRUISE indicator is also used during cruise control system diagnosis.
System Operation
To Set Cruise Control
Caution: Do not use the cruise control on slippery roads, steeply graded roads,
or in heavy traffic of heavy or varying volume. Failure to follow these CAUTIONS
could possibly cause you to loose control of the vehicle and result in damage
to the vehicle and personal injury.
- Drive the vehicle above 40 km/h (25 mph).
- Depress and release the CRUISE ON OFF button.
- Accelerate to the desired speed.
- Move the cruise control switch downward to the SET/COAST position
and release.
- Take your foot off the accelerator pedal.
To Resume a Set Speed
Suppose you set your cruise control at a desired speed and then you
apply the brake. This, of course, shuts off the cruise control. But you do
not need to reset it. Once you're going 40 km/h (25 mph)
or more, you can move the cruise control switch upward to the RES/ACC
position and release. You will go right back up to your chosen speed
and stay there. If you turn the ignition off, or turn cruise switch
off, you will erase memory.
To Get Out of Cruise Control
There are 3 ways to turn off the cruise control.
• | Step lightly on the brake pedal. |
• | Depress and release the CRUISE ON OFF button. |
• | Depress the clutch pedal (manual transmissions). |
Passing Another Vehicle While Using Cruise Control
Use the accelerator pedal to increase your speed. When you take your
foot off the pedal, your vehicle will slow down to the cruise control speed
you set earlier.
To Increase Speed While Using Cruise Control
There are two ways to gain higher speed while using cruise control.
• | Use the accelerator pedal to get to the higher speed, move the
cruise control switch downward to the SET/COAST position and release. You
will now cruise at the higher speed. |
• | Move the cruise switch upward to the RES/ACC position, hold it
there until you get up to the speed you want and release. To increase your
speed in very small amounts, move the cruise control switch upward to
the RES/ACC position for less than 3/4 of a second and release it.
Each time you do this, your vehicle will go approximately 1.6 km/h (1
mph) faster. |
The accelerate feature will only work after you turn on the cruise control
by pushing and releasing the ON OFF button and setting a cruise control speed.
Using Cruise Control on Hills
How well your cruise control will work on hills depends upon your speed,
load, and the incline of the hills. When going up steep hills, you may have
to step on the accelerator pedal to maintain your speed. When going
downhill, you may have to brake or shift to a lower gear to keep your
speed down. Of course, applying the brake takes you out of cruise control.
Many drivers find this to be too much trouble and do not use cruise
control on steep hills.
To Erase Cruise Speed Memory
When you turn off the cruise control or the ignition is turned off,
your cruise control set speed memory is erased.
To Reduce Speed While Using Cruise Control
There are 2 ways to reduce your speed while using cruise control.
• | Move the cruise control switch downward to the SET/COAST position
and hold until you obtain the lower speed you want. Then release it. |
• | To slow down in very small amounts move the cruise control switch
downward to the SET/COAST for less than 3/4 of a second and release. Each
time you do this, you will go approximately 1.6 km/h (1 mph) slower. |
Circuit Operation
Battery voltage is applied to terminal 4 of the cruise control
module when the ignition switch is in the ON position. When the cruise control
switch is pressed to the CRUISE ON OFF position, ground is applied to
the internal switch of the cruise control module at terminal 11.
The cruise control switch signals the cruise control module (CCM) at
terminal 10 to enter the CANCEL, SET/COAST, or RES/ACC by using varying
amounts of resistance depending on the mode selected.
Ground is supplied to the CCM at terminal 16 from G203.
Outputs from the CCM are found on the following terminals:
• | 4 cruise control indicator (completes the circuit to light the
cruise control indicator) |
• | 5 DLC (provides flash codes to the DLC) |
• | 8 magnetic clutch (for the servo motor) |
• | 14 O/D cut control (informs the PCM to downshift from overdrive) |
Inputs to the CCM are found on the following terminals:
• | 2 brake signal (disables cruise when the brake pedal is pressed) |
• | 3 cruise interrupt signal (transaxle range switch not in DRIVE
(D) or clutch pedal pressed) |
• | 6 shift solenoid 2 control (informs the CCM when the transaxle
is in 2nd or 3rd gear and is out of overdrive mode |
• | 10 cruise control switch (mode switch) |
• | 11 cruise control ON OFF |
• | 12 vehicle speed (from the PCM) |
• | 13 idle signal control (informs the ccm when the accelerator is
pressed and engine is above idle) |
Cruise control will be disabled when one or more of the following conditions
exist:
• | The VSS is less than 25 mph. |
• | The transaxle range switch indicates that the vehicles is not
in DRIVE (D). |
• | The clutch pedal is depressed (manual transaxle). |
• | There is an over/under battery voltage condition. |
• | The brake pedal is pressed |
• | The engine RPMs are low (idle). |