One problem related to automatic transmission control module has been reported for the 2006 GMC Envoy. The most recently reported issues are listed below.
Vehicle goes into reduced engine power mode unexpectedly while driving with no prior warning. Mil light turns on, reduced engine power light turns on, stabilitrak off dic message displays, results in loss of acceleration and requires the driver to immediately take emergency safety actions. Codes include p2135, p0121, and p060e. Issue is intermittent, appears more frequently in cold or wet conditions. The issue has occurred more than 10 times since the initial incident. Dealer unable to correct the issue by throttle body cleaning and pcm replacement. Latest attempt is to replace the throttle body.