18-020-15 REV-A

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 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: ? 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.