They are talking about code 26, upshift delay.
The problem is the upshift vac element or hose at the tranny has a vac leak.
the test is to pull a vac on that line with a hand pump and see of it holds.
Reset is under hood at the diagnostic led/sw box[11x/2]
After code comes up, hold button for 8 secs, key off for 10sec , on for 10
CE will go out