The powertrain control module (PCM) will command the cruise control module to control the throttle when the following conditions are true:

Important: On automatic transaxle equipped vehicles, the PCM will not allow cruise operation until a brake switch transition is seen.

1. The cruise switch is ON.
2. The vehicle speed is greater than 40 km/h (25 mph).
3. The RES/ACCEL or SET/COAST switches have been depressed for a minimum period of 0.06 seconds.
4. The cruise control cannot be engaged with the RES/ACCEL switch until the SET/COAST has been used to make the initial set.
5. The brake pedal is not depressed.
6. The clutch is fully engaged, manual transmission only.

Engaged cruise control will be disengaged if any of the following driver induced conditions exist:

Engaged cruise control can also disengage if the PCM detects any one of the following conditions:

Set/Coast Switch

The SET/COAST switch has several functions:

1. When cruise is enabled, pressing the SET/COAST switch will engage cruise. The switch must be pressed for a period greater than 0.06 seconds, but less than one second.
2. When cruise is engaged, holding the SET/COAST switch depressed will allow the vehicle to coast down to a new, lower cruise speed. The switch must be pressed for a period greater than 0.4 seconds.
3. When cruise is engaged, tapping the SET/COAST switch will cause the cruise set speed to be lowered in increments of one mile per hour for each momentary press of the SET/COAST switch. This is the TAP DOWN feature. The switch must be pressed for a period greater than 0.06 seconds, but less than 1.4 seconds.

Res/Accel Switch

The RES/ACCEL switch has several functions:

1. If the vehicle has been in cruise engaged mode, and cruise has been disabled by pressing the brake and/or clutch pedals, the vehicle can be returned to the original set speed by pressing the RES/ACCEL button one time. The switch must be pressed for a period greater than 0.06 seconds, but less than 1 second.
2. Holding the RES/ACCEL switch in the accelerate position will cause the vehicle to accelerate until the switch is released, resulting in new cruise speed. The switch must be pressed for a period greater than 1.4 seconds.
3. When cruise is engaged, tapping the RES/ACCEL switch will cause the cruise set speed to be raised in increments of 2 km/h (1 mph) for each momentary press of the RES/ACCEL switch. This is the TAP UP feature. The switch must be pressed for a period greater than 0.06 seconds, but less than 1.4 seconds.

Switch Debounce

Once the SET/COAST, ON/OFF, or the RES/ ACCEL switch is pressed, it must remain pressed at least 0.06 seconds to be considered a valid switch closure.

Tap Up and Tap Down Cruise Set Speed Adjustment

The desired set speed can be adjusted UP and DOWN in 2 km/h (1 mph) increments after (and while) cruise is engaged. The system will limit the number of TAP UP requests to a differential of 10 mph from the previously recognized set speed.

Tap Up Feature

The desired set speed is adjusted up by momentarily depressing the RES/ACCEL switch. This is the TAP UP feature. To be considered a valid TAP UP request, the RES/ACCEL switch must be pressed between 0.06 and 1 second. Pressing the RES/ACCEL switch longer than 0.7 seconds will be considered an accelerate command. Each press of the RES/ACCEL switch, which is determined to be a valid TAP UP request, will cause the desired set speed to be increased by one mile per hour. Holding the RES/ACCEL longer than 1.4 seconds results in a new set speed upon release of the button.

Tap Down Feature

The desired set speed is adjusted down by momentarily depressing the SET/COAST switch. This is the TAP DOWN FEATURE. To be considered a valid TAP DOWN request, the SET/COAST switch must be pressed between 0.06 and 1 second. Each press of the SET/COAST switch (which is determined to be a valid TAP DOWN request) will cause the desired set speed to be decreased by 2 km/h (1 mph).

Tap Down Lower Speed Limit

When issuing repeated TAP DOWN requests, the cruise set speed is limited to 40 km/h (25 mph), and cannot be tapped down below that limit.

Combination Tap Up and Tap Down Resolution

When the driver issues a combination of TAP UP and TAP DOWN requests, the cruise set speed is adjusted according to the total sum of the TAP UP and TAP DOWN requested. For example, if the driver TAPS UP five times, then TAPS DOWN once, the speed will increase by 6 km/h (4 mph).

The cruise control system is used to control vehicle speed to a user selected value and an accuracy of ± 2 km/h (1 mph) on a flat level road (± 2 percent grade).

The system consists of a cruise control module; located in the passenger compartment on the driver's side above the accelerator pedal, cruise control switches, stop lamp switch and PCM.

Unlike other cruise control systems, this system is fully electronic and does not require vacuum or a vacuum servo motor to control the movement of the throttle. To control throttle movement, a rod from the cruise control module pulls on the accelerator linkage at the accelerator pedal.

The cruise control system is an integration of the cruise control module and PCM. Cruise control signals go directly to the PCM, which in turn uses engine control sensors to evaluate and command cruise control movement, cruise control direction and enable/disable of the cruise control module clutch.

The stop lamp switch is used as an input to the PCM to enable/disable the cruise control clutch ground. With the brake pedal released, the stop lamp switch also allows ignition voltage at the cruise control module. This voltage turns a driver ON which allows current to flow to the cruise control clutch. When the brake pedal is depressed, the PCM will open the ground circuit and the cruise control module will open the ignition voltage circuit to the cruise control clutch. This ensures that the clutch is turned Off when the brake pedal is depressed.

The cruise control module uses the cruise control clutch to engage the drive motor to the attachment rod mechanism. The speed and direction at which the rod moves is determined by the PCM and conveyed to the cruise control module through the cruise control move and direction circuits. The PCM will supply ignition voltage on the cruise control direction circuit when the accelerator pedal needs to move toward wide-open-throttle to maintain cruise set speed. If the PCM commands the pedal toward idle, the voltage will go low. When no movement is needed, the PCM defaults to the toward idle state.

The PCM pulse width modulates ignition voltage on the cruise move circuit which provides the amount and speed movement of the accelerator pedal. Very short ON-time pulses indicate a steady accelerator position. The longer the ON-time pulses, up to a 90 percent duty cycle, the faster the accelerator pedal will move.

The PCM performs circuit checks on the cruise control system and can set diagnostic trouble codes if a fault is detected. The PCM monitors the stop lamp circuit, cruise control switch circuit, cruise control clutch circuit, cruise control move circuit and the cruise control direction circuit. If the PCM disabled cruise control due to a fault, DTC P1584 will set and specific information regarding which type of fault set the DTC can be viewed under the Scan tool Failure Record. After verifying a cruise control problem exists, retrieving DTCs should be the first step in diagnosing a cruise related problem.

The Scan tool can perform a special function which can simulate cruise control module rod movement. The test will move the accelerator pedal to 50 percent throttle and back down to idle. This function checks the ability of the PCM to control the cruise control clutch, direction and move circuits. The Scan tool can also display the cruise switch as well as the stop lamp switch, brake switch, states.