Without 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 refer to Powertrain Management/Computers and Control Systems/Testing and Inspection/Procedures otherwise use the following procedure:

If a DRB II or equivalent scan tool is not available, check for fault (trouble) codes as follows:
1. Cycle ignition switch ON then OFF three times. On third cycle, leave switch in ON position.
2. Observe Check Engine Lamp in instrument cluster. Indicator lamp will flash (blink) in a series which will show which fault (trouble) codes are set in memory.
3. If fault (trouble) code 34 is observed, determine source of problem by performing tests, refer to SPEED CONTROL SYSTEM TESTS. Refer to SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC DIAGRAMS for speed control system wiring diagrams.
4. If fault (trouble) code 15 is present, testing of the distance sensor is required. Testing of the distance sensor requires the use of the DRB II diagnostic tool.
5. On 1991 Dodge Monaco & Eagle Premier, if fault (trouble) code 77 is present, refer to Cruise Control/Cruise Control Relay/Testing and Inspection/Procedures.
6. On all models, if no problems were found, replace engine controller.