Cruise Control Systems: Self-Diagnostics: Introduction
- Testing of EEC-IV controlled cruise control is separated into 2 parts: QUICK-TESTS and CIRCUIT TESTS. QUICK-TESTS are functional, checking all cruise control components except VSS. VSS must be tested separately.
- When testing cruise control system, perform appropriate QUICK-TEST first. If system passes, test VSS. If system has retained trouble codes, perform appropriate CIRCUIT TEST for stored codes only. When all testing and repairs are complete, repeat appropriate QUICK-TEST to verify cruise control system works properly.
- The following steps must be carefully followed in sequence, otherwise misdiagnosis, or unnecessary replacement of components may result:
- VISUAL CHECK & VEHICLE PREPARATION
- EQUIPMENT HOOK-UP
- KEY ON, ENGINE OFF (KOEO) TEST
- KEY ON, ENGINE RUNNING (KOER) TEST
NOTE:
Correct results for QUICK-TESTS are dependent on correct operation of related non-cruise control components and systems. All non-cruise control problems should be corrected before attempting to diagnose cruise control system.