Reading and Clearing Diagnostic Trouble Codes

When trying to verify a speed control system electronic malfunction: Connect a DRB scan tool if available to the data link connector. The connector is located at left side of the steering column, and at lower edge of the panel.
1. A speed control malfunction may occur without a diagnostic code being indicated.

Speed Control Slows Down By Itself
Test vehicle speed sensor. If sensor fails replace sensor, if it passes perform the following test:
1. Perform the speed control switch test on the DECEL switch, if it fails replace switch.
2. If the switch passes, conduct the vacuum supply test.
3. If it passes, conduct the servo vacuum test. If it fails replace servo.
4. If continuity, replace the PCM.