Lexus thermostat DTC

Some 2008-2009 Lexus vehicles equipped with the 2GR-FSE or 4GR-FSE engine may exhibit a MIL-on condition with DTCs P0128 (coolant thermostat below thermostat regulating temperature) and/or P0116 (engine coolant temperature range/performance problem).

This applies to 2008-2009 GS350, GS450H, IS250 and IS350 vehicles produced BEFORE the production change effective VINs as follows:

MODEL         PLANT                DRIVE              PROD. CHANGE EFFECTIVE VIN

GS350         Tahara                2WD                   JTHBE96S*90045581

GS350         Tahara                4WD                   JTHCE96S*90023172

GS450h       Tahara                2WD                   JTHBC96S*95019778

IS250           Tahara                4WD                   JTHCK262*95033047

IS250           Tahara                2WD                   JTHBK262*95099794

IS250           TMK                     4WD                   JTHBK262*92094026

IS350           Tahara                2WD                   JTHBE262*95023043

IS350           TMK                     2WD                   JTHBE262*92017385

REQUIRED TOOLS AND EQUIPMENT

TIS Techstream (software version 4.21.002 or later is required)

Super Long Life Coolant P/N 00272-SLLC2 (9.6 – 9.8 U.S. qts)

PREVIOUS P/N      CURRENT P/N               ITEM

16031-31020               SAME                       Water w/thermostat inlet sub-assembly

 Using Techstream, check for any stored DTCs.

1. If DTCs P0128 and/or P0116 are present, remove and inspect the thermostat housing and thermostat. If the thermostat assembly is securely seated in the thermostat housing, this TSB does not apply. Refer to the repair manual and follow diagnostics for the DTC(s). If the thermostat is not securely seated, refer to the repair manual for the specific vehicle for removal/installation of the thermostat assembly.
2. Once the repair complete and verified, clear all DTCs.