Two-Trip Detection Logic

When a malfunction initially occurs, Diagnostic Trouble Code (DTC) will be temporarily stored in ECM memory, but MIL on instrument panel will not illuminate. The second time malfunction is detected, MIL on instrument panel will illuminate, provided ignition is turned off and then back on after first malfunction was detected. This is referred to as the 2-Trip Detection Logic and only applies to specified DTCs. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table under SELF-DIAGNOSTIC SYSTEM.

NOTE: When road testing vehicle in CHECK mode (Lexus scan tester only), the Two Trip Detection Logic will not function. Also, MIL will illuminate first time a malfunction is detected.