This bulletin applies to 2010-2011 Buick LaCrosse models equipped with the 3.6L V6 engine, built prior to VIN breakpoint BF358708. Some customers may comment that the MIL is illuminated within the first 60 seconds of operation after a cold start.
A revised calibration has been developed to address this condition. Technicians may observe a DTC P0300 through P0306 (random misfire counts).
Review the service manual to diagnose this condition. If the service manual does not isolate a fault, reprogram the ECM with updated calibration files using the TIS2Web Service Programming System (SPS) application. Select SEQ Programming Sequence ECM/TCM from the supported controllers screen.
Calibrations include multiple updates. Confirm that the newest calibration includes the following description: “P0300 cold start, low ambient temperature-low misfire counts, first 60 seconds.”
This calibration should only be used to repair vehicles that have the subject condition.