18-033-25

Flash: Powertrain Control Module (PCM) Updates *Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):
• **P0420 - Catalyst System Efficiency Below Threshold Bank 1.
• P0430 - Catalyst System Efficiency Below Threshold Bank 2.**
• P0456 - EVAP System Small Leak.
• P06EF - Engine Restart Performance.
• P0175 - Fuel System 2/1 Rich.
• P258B - Electronic Vacuum Pump Performance.
• P0128 - Thermostat Rationality.
• C0062 - Longitudinal Acceleration Sensor. In addition, the customer may experience one or more of the following:
• **Vehicle fails emissions inspection testing due to OBD catalyst monitor readiness.**
• Engine RPM erratic and or bucking, when accelerating after slowing down.
• Occasional engine shut off while shifting from 4WD low to 2WD.
• Improvements to the vacuum pump cycle time.
• Rough idle after cold start. This bulletin involves reprogramming the PCM with the latest available software.