E320 (w124?) trouble codes
 

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:

http://www.peachparts.com/shopforum/tech-help/35730-e320-fault-code-26-a.html