Unfortunately the check engine light must be working on your 1996 Mercedes
Benz S320 in order for it to pass the smog check. The check engine light not
working is an emission related fault and can be covered under the State's
Consumer Assistance program. You might want to look into apply for it. In
the mean time the most time you will be offered to get the repairs need to
get the check engine light working is a 30 day temporary registration tag
through the DMV.
If you apply for CAP the process might take longer then 30 days so you'll
need to revisit the DMV and get a second 30 day pass, but there is no
waiver.
