C7 Auto Trans
Thread Starter
Cruising
Joined: Feb 2018
Posts: 13
Likes: 0
From: Hauppauge New York
C7 Auto Trans
Regarding C7 auto-trans; I have a 2016 Z-51 with an automatic trans, while out driving on the parkway at approximately 55mph I changed lanes the car downshifted and brought her up to approximately 70+- mpg. When I let up on the gas the car remained in the lower gear. I then tried using the paddle shifters, but that didn’t work. I had to get over onto the shoulder and shut it down, restarted the car and was fine. There was no, Check Engine light on. I stopped by my dealer and they said they have never seen or heard of this problem? I googled this issue and found another with a similar shifting problem, he went to the dealer and they said it was the “Knock Sensor” ?
Your imput, is much appreciated.
Thank you
Your imput, is much appreciated.
Thank you
Safety Car
Joined: Aug 2012
Posts: 3,960
Likes: 1,106
You sure you weren't just in PAS/PAL mode triggered by sharp acceleration and a turn into the other lane? Performance Algorithm Shift/Performance Algorithm Lift foot are two related shift strategies used in a lot of current GM automatic transmissions to provide better performance during aggressive driving maneuvers. The powertrain controller anticipates that the driving behavior that required a lower gear will likely continue so rather than immediately upshift a lower gear is held for several seconds of normal driving.
I have never tried to paddle upshift when PAS/PAL was active but the first time you trigger this behavior it will get your attention. I first ran across this back in 2008 with my 2nd gen CTS. I had just finished its initial break-in period and went to high throttle coming off an interstate merge lane and it stayed in a lower gear for several seconds of normal driving before deciding I was through with insane driving and went back into normal shift mode.
I have never tried to paddle upshift when PAS/PAL was active but the first time you trigger this behavior it will get your attention. I first ran across this back in 2008 with my 2nd gen CTS. I had just finished its initial break-in period and went to high throttle coming off an interstate merge lane and it stayed in a lower gear for several seconds of normal driving before deciding I was through with insane driving and went back into normal shift mode.
Last edited by NSC5; Jun 18, 2018 at 08:00 AM.
Melting Slicks
Joined: Jun 2004
Posts: 2,130
Likes: 54
From: Granbury, Pecan Plantation TX
You sure you weren't just in PAS/PAL mode triggered by sharp acceleration and a turn into the other lane? Performance Algorithm Shift/Performance Algorithm Lift foot are two related shift strategies used in a lot of current GM automatic transmissions to provide better performance during aggressive driving maneuvers. The powertrain controller anticipates that the driving behavior that required a lower gear will likely continue so rather than immediately upshift a lower gear is held for several seconds of normal driving.
I have never tried to paddle upshift when PAS/PAL was active but the first time you trigger this behavior it will get your attention. I first ran across this back in 2008 with my 2nd gen CTS. I had just finished its initial break-in period and went to high throttle coming off an interstate merge lane and it stayed in a lower gear for several seconds of normal driving before deciding I was through with insane driving and went back into normal shift mode.
I have never tried to paddle upshift when PAS/PAL was active but the first time you trigger this behavior it will get your attention. I first ran across this back in 2008 with my 2nd gen CTS. I had just finished its initial break-in period and went to high throttle coming off an interstate merge lane and it stayed in a lower gear for several seconds of normal driving before deciding I was through with insane driving and went back into normal shift mode.
Thread Starter
Cruising
Joined: Feb 2018
Posts: 13
Likes: 0
From: Hauppauge New York
