Intermittent Loss of Power, Rough Running Engine at Start Up (Reprogram PCM)

Some customers may comment on a intermittent loss of power or rough running engine when the vehicle is placed in DRIVE at initial start up only.

There may not be any DTCs set when this condition occurs. Typically, this will only occur if the driver starts the engine, immediately places the shifter into D3 and accelerates (all within a couple seconds - as when someone is in a rush to get somewhere). If this sequence of events occurs at a slower pace, this concern will not occur. Due to the shifter release mechanism being on the front of the shifter, the shifter may easily be placed into D3 instead of D4 when rapidly pulling back on the shifter. As a result, some customers may not realize that the shifter was in D3 when this occurred.

The PCM may interpret the rapid placement into drive and enter transmission abuse management mode, which will limit the throttle position desired and actual angles to a maximum of 45%, even if the accelerator pedal is pushed to wide open throttle. Rather than coming out of this mode though, the PCM will stay in this mode until the ignition is cycled or until the shifter is moved to PARK, REVERSE or NEUTRAL and then back into D4.

Important: Before reprogramming the PCM, verify the customer concern. Follow published diagnostics in SI. If not trouble is found, reprogram the PCM.

A revised engine calibration has been developed to address this issue. Reprogram the PCM with an updated software calibration. This new service calibration is available on TIS2WEB using the Service Programming System (SPS). As always, make sure your Tech 2® is updated with the latest software version.

For vehicles repaired under warranty, use: