SUBJECT REGARDING ELECTRONIC CONTROL UNIT (ECU) REPROGRAMMING SUPPORT. CERTAIN 2001 FOUR CYLINDER VEHICLES, IF DRIVEN AT TEMPERATURES BELOW 30 DEGREES F, MAY DISPLAY A MALFUNCTION INDICATOR LAMP (MIL) AND STORE ONE OR MORE OF THE FOLLOWING DIAGNOSTIC TROUBLE CODES: P0171, P0174, P1130, P1133, P1150, OR P1155. IF THESE CODES ARE SET, AIR / FUEL RATIO SENSORS, BANK ONE, SENSOR ONE AND BANK TWO, SENSOR ONE ARE LIKELY DAMAGED AND BOTH SENSORS WILL NEED TO BE REPLACED. TO AVOID DAMAGING THE REPLACEMENT AIR / FUEL RATIO SENSORS DURING COLD WEATHER DRIVING THESE VEHICLES WILL NEED THEIR ECU REPROGRAMMED. *TT