Diagnostic Tests: Notes

NOTE: Before performing any diagnostic test, see SELF-DIAGNOSTICS - INTRODUCTION article for diagnostic system functions and system diagnostic procedures. To identify circuits and wire colors referenced in testing, see WIRING DIAGRAMS. Use illustration to identify ECM connector terminals. See Fig 1. References to California emissions apply to vehicles with California emissions, which may be verified by underhood Emission Control label. Vehicles with California emissions may be available in other states.

Fig 1: Identifying Engine Control Module (ECM) Harness Connector Terminals