Maybe I'm ignorant and the codes and descriptions are the same but I thought code 26, (which I also have currently on my '94 wagon) is:

"26 Upshift delay switch over valve-open or shorted. "

I think it delays the shift from 2nd to 3rd when the car is cold until the cat warms up, non?

__________________
dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles