Introduction to Cruise Control System Diagnosis

The auto-cruise control system allows driving without stepping on the accelerator pedal by setting a random speed between 40 kph (25 mph) and 200 kph (124 mph). Troubles in this system can be investigated with the following methods.

Auto-cruise control system diagnostic trouble codes
The auto-cruise control system consists of the auto-cruise control-ECU, control switches, sensors, and vacuum pump. The control switches and sensors monitor the state of the vehicle. Based on input signals from those switches and sensors, the auto-cruise control-ECU activates the vacuum pump. If the auto-cruise control-ECU detects a problem on any of those components, the ECU estimates where the problem may be occurring, and will output a diagnostic trouble code. Diagnostic trouble codes cover the throttle position sensor, auto-cruise control switch, vehicle speed sensor, auto-cruise control-ECU and vacuum pump.