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.
