Hesitation or Stumble on Throttle Application After Cold Start (Reprogram PCM)

Some owners may comment on a hesitation or stumble on throttle applications after a cold start at temperatures below approximately 50°F (10°C). This condition will not occur after the vehicle has warmed up and has been operating in closed loop. No PCM diagnostic trouble codes will be stored and no MIL will illuminate.

In some instances, the PCM fueling strategy may not be optimized during throttle application conditions at low coolant temperatures.

Reprogram the vehicle PCM with new calibration software.

The Calibrations are electronic calibrations and are not available from GMSPO. For 1999, 2000, and 2001 model year vehicles, calibrations are currently available from Techline using the Service Programming System (SPS). After entering the VIN for the vehicle to be reprogrammed, use the calibration identified as "New Calibration to Address Cold Hesitation Problem" on 1999 and 2000 vehicles. On 2001 models, the calibration to correct the cold hesitation is included in the "New Cal to Correct False Setting of DTC P0441".

Important: Model Year 2000 vehicles with this concern may also be subject to USA and IPC Customer Satisfaction Campaign #01028B - Generator Low Voltage Indicator Light PCM Reflash or Canada CMVSS Non-Compliance Campaign #01029B - Generator Low Voltage Indicator Light PCM Reflash. The calibrations released for the hesitation concern also incorporate the calibrations for Campaigns #01028B and #01029B. Because these 2000 model year vehicles with 2.4L LD9 engines may need to be reflashed twice, it is important to manage the situation in such a way as to maximize customer satisfaction while minimizing customer inconvenience.

For vehicles repaired under warranty, use: