Diagnostic Tests: Notes

NOTE: Before performing any diagnostic test, refer to SELF-DIAGNOSTICS - INTRODUCTION article for diagnostic system functions and system diagnostic procedures. For component location, see appropriate illustration in THEORY & OPERATION article. To identify circuits and wire colors referenced in testing, see appropriate wiring diagram in WIRING DIAGRAMS article.

NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY & OPERATION article.

CAUTION: If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.