With Scan Tool
When trying to verify a speed control system electronic malfunction, one of two methods may be used. If a DRB II or equivalent scan tool is available use the following procedure, otherwise refer to Powertrain Management/Computers and Control Systems/Testing and Inspection/ProceduresIf a DRB II or equivalent scan tool is available, follow tool manufacturers instructions for proper installation of the tool prior to testing speed control system. Plug tool into diagnostic connector and verify that either a fault (trouble) codes 15 or 34 on except 1991 Dodge Monaco & Eagle Premier is indicated or fault (trouble) codes 15, 34 or 77 on 1991 Dodge Monaco & Eagle Premier is indicated, refer to DIAGNOSTIC CHARTS.
If no problems were found, replace engine controller.