Cruise Control Diagnosis

Cruise Control Diagnosis






Circuit Description

The cruise control system is a speed control system that maintains a desired vehicle speed under normal driving conditions. The cruise control system has the following capabilities:

* Cruise
* Coast
* Resume speed
* Accelerate
* Raise (Tap-up) the vehicle speed by 1.6 km/h (1 mph)
* Lower (Tap-down) the vehicle speed by 1.6 km/h (1 mph)

The throttle actuator control (TAC) module controls the cruise system. When the cruise control switch is in the ON position and you push the cruise SET/COAST switch, the TAC module maintains the current vehicle speed. If the engine load varies, the TAC module commands the throttle blade to the appropriate position in order to maintain the desired vehicle speed.

The cruise control system consists of the following components:

* The TAC module
* The TAC motor
* The cruise control actuator lever

Conditions for Enabling the Cruise System

* The cruise switch is in the ON position.
* Ignition voltage is present to the cruise actuator lever.
* The vehicle speed is more than 39 km/h (24 mph).
* The brake pedal is not depressed.
* The transmission is in a forward gear.
* The engine is not in Engine Coolant Over Temperature-Fuel Disabled Mode.
* The cruise SET/COAST switch has been pushed and released.

Conditions for Disabling the Cruise System

* The cruise switch is turned to the OFF position.
* Ignition voltage is interrupted to the cruise actuator lever.
* The vehicle speed is less than 32 km/h (20 mph).
* The brake pedal is depressed.
* The engine is in Engine Coolant Over Temperature-Fuel Disabled Mode.
* The transmission is placed into neutral.
* A problem with brake pedal switches or circuits that the TAC module interprets as the pedal is applied.

Diagnostic Aids

Use the scan tool in order to monitor the Cruise Disengage History. This parameter lists the last 8 cruise disengage events. Refer to Cruise Disengage History table for a description of each condition.

The cruise control system disables for the current ignition cycle if an intermittent condition exists.