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 that a 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 tool only), the Two Trip Detection Logic will not function. Also, MIL will illuminate first time a malfunction is detected.