Diagnostic Tests: Notes

WARNING: This page is about a different car, the 2003 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Perform all resistance and voltage tests with a Digital Volt-ohmmeter (DVOM) with minimum 10-megohm impedance, unless stated otherwise in test procedures. Ensure ignition switch is in OFF position when performing resistance tests.

CAUTION: If ECM replacement is instructed in following testing, always ensure ECM harness connector 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 - LEXUS article in GENERAL INFORMATION.

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

NOTE: For identification of circuits, terminals and wire colors not referenced in following testing, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.