Introduction to Auto-Cruise Control System Diagnosis

The auto-cruise control system allows driving without stepping on the accelerator pedal by setting a random speed between 40 km/h (25 mph) and 200 km/h (124 mph).

Problems in this system can be investigated by 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.