california smog readiness flags on 1996 Mercedes-Benz C280

I have a 1996 c280, 165000 miles due for a biannual smog test. If failed the first test due to not all readiness flags not being set. I have taken it to several friends shops( I am a tech myself) and they are unable to get them to set. We have a complete drive cycle sheet showing exactly conditions to set the monitors. We have driven this cycle multiple times and have driven over 2000 miles since then. I have been told it may be the DME. Is there anyway of telling exactly what is at fault without shelling out $2000.? Are DMEs interchangeable from other c280s? Thanks for your help.

2 answers 1 comment
I too have a 1996 C280 and its a known issue. You need to take your failed smog test results and have BAR (California Bureau of Auto Repair) Referee center smog it. I've done it for my last 3 smogs. Its something to do with 96 c280s and OBDII. Here's their number for more info. (800) 622-7733
Hi there I have a 1996 C280 that keeps getting rejected because the EGR, Secondary Air, and Catalyst Monitors will not set. I have driven the car through the drive cycles, brought it to multiple shops and no one seems to know what is going on with it. I live in las Vegas and apparently i cannot get an exemption unless the car fails the smog and it is just getting rejected because the monitors will not set. PLEASE HELP
Scantool information should be able to identify which monitors have not passed. Is it Evaporative , EGR, catalytic converter efficiency? I have gotten a lot of cars to pass monitor tests and have friends that are well up on Mercedes problems if you can tell me which monitors presently don't pass.