18-020-15 REV-B

Flash: Driveability Enhancements This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the Technician may find that the following Diagnostic Trouble Codes (DTCs) have been set: ? P1128 - Closed Loop Fueling Not Achieved - Bank 1 Upstream ? P1D73 - 00 - AGS Performance ? P1CEA - Boost Side Evap Purge System Performance ? P0456 - Evap System Small Leak Customers may also experience any of the following symptoms: ? Customer experiences cold start issues below 14°F ( -10°C) ambient temperatures; engine turns over faster (loss of compression) during crank and possibly does not start until a key cycle is performed. ? Engine cranks as if it has no compression. ? Engine sounds like it is knocking at idle, noise goes away when off idle. ? Spark knock when using low octane fuel in the vehicle. ? Black smoke from tail pipe on initial start up during cold ambient temperatures. ? Uneven acceleration feeling under moderate to heavy throttle input. ? Bump or surge noticed prior to engine reaching normal operating temperature. ? Rough idle during A/C engagement/disengagement. ? During periods of extended idle or short hot soak events and ambient temperatures below 15°F (-9°C), engine idle speed may increase to 1800 RPM if coolant temperature drops below 158°F (70°C). Condition is only present when the transmission is in park. ? Low speed engine response improvements in city and traffic driving conditions. Updating the PCM software will correct the condition listed above.