TSB: ECU UPGRADE ? MIL ON WITH DTC(s) P0420/P0171 - This bulletin provides information related to the ECU software upgrade for some 2012~2015MY Optima (QF) vehicles, produced from August 12, 2011 to October 2, 2015, some 2012~2015MY Sorento (XMa) vehicles, produced from April 19, 2011 to December 11, 2014, some 2011~2015MY Optima (TF) vehicles, produced from August 12, 2010 to July 23, 2015, and some 2014~2016MY Sportage (SL) vehicles, produced from September 30, 2013 to November 16, 2015, which may experience a malfunction indicator lamp (MIL) illuminated with the Electronic Control Unit (ECU) system-related DTC(s): P0420 and possibly P0171. This concern occurs most commonly during prolonged engine braking while descending a steep grade.
