I'm having trouble with a DM code 26, my scanner says cat effectiveness, but my other searches say upshift delay. Where should i be looking? And how can the cat converter effectiveness be monitored with out an after cat O2 sensor? any help would be appreciated. thanks.

Code #26 on an M104 W124 is a fault in your upshift delay valve.

This is your lucky day. There's a good thread going on right now about this fault code:

E320 fault code 26

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".