Cruise Control Description and Operation 2.2L
Cruise control is a speed control system that maintains a desired vehicle
speed under normal driving conditions. However, steep grades may cause variations
in the selected speeds. The electronic cruise control system has the capability
to CRUISE, COAST, RESUME SPEED, ACCELERATE, and TAP-UP or TAP-DOWN.
The main parts of the cruise control system are:
| • | The cruise control module assembly |
| • | The function control switches |
| • | The cruise control release switch |
| • | The stop lamp switch assembly |
The cruise control system uses the cruise control module assembly to
maintain the desired vehicle cruise speed and operation. The cruise control
module assembly has electric stepper motor to vary the throttle in each different
cruise control mode. The engine control module (ECM) monitors vehicle speed
and operates the electric stepper motor. The stepper motor operates in response
to the ECM, to maintain the desired cruise speed. The electric stepper motor
moves a strap that is attached to the cruise control cable which moves the
throttle pedal. The ECM contains a low speed limit which will prevent system
engagement below a minimum speed of 40 km/h (25 mph). The cruise control module
assembly is not serviceable.
The function control switches located on the steering wheel are inputs
to the ECM. The cruise control functional control switches include the ON/OFF,
SET/COAST and R/A switch. The switch assembly provides driver control of the
cruise control system. The ECM receives a distinct voltage level on the Cruise
Control Set/Coast and Resume/Accelerate Switch Signal circuit from the cruise
control switch assembly. The voltage level depends on the current switch position.
Once the switch position is determined the ECM will command the cruise control
module accordingly.
The ECM controls the cruise control module through three control circuits.
The Cruise Control Servo Move Signal circuit controls the rate of speed and
magnitude of pedal movement. The Cruise Control Servo Move Direction Signal
circuit controls the direction of pedal movement, either toward wide open
throttle (WOT) or idle. The Cruise Control Servo Clutch Control circuit engages
or releases the stepper motor to the cruise control cable drive mechanism.
The TCC/Brake switch and the stop lamp switch control both the cruise
control release signal and stop lamp signal. These signal circuits are used
to disengage the cruise control. The TCC/Brake and stop lamp switch assembles
are mounted on the brake pedal bracket. When the brake pedal is released,
the TCC/Brake switch is closed providing ignition voltage to the brake input
of the cruise control module. The stop lamp switch is a normally open switch
that provides ignition voltage the ECM when the brake pedal is depressed.
If a fault is determined in either the TCC/Brake switch or stop lamp switch,
cruise will be disabled.
With cruise control, you can maintain a speed of about 40 km/h
(25 mph) or more without keeping your foot on the accelerator.
When the driver turns off the on/off switch, or the ignition switch, the cruise
control turns off. The vehicle speed stored in the memory of the ECM will
be lost. If the driver disengages cruise by depressing the brake pedal, vehicle
speed will be stored in memory for the rest of the ignition cycle and can
be resumed by depressing the Resume/Accel switch.
The ECM will inhibit cruise control:
| • | When vehicle speed is less than 40 km/h (25 mph) |
| • | When in PARK, REVERSE, NEUTRAL, or 1st gear |
| • | When vehicle speed is to high |
| • | When an over or under charged battery voltage condition exists |
| • | Antilock brake system/traction control system is active for more
than 1 seconds |
| • | When a brake switch failure is present |
| • | A fault relating to vehicle speed is present |
If the ECM determines that any of the cruise control inhibit conditions
are present, the ECM will disengage the cruise control.
