OBD-2 first appeared on a few select 1995 gasser models, and is on all 1996s. Diesel's were required to have it for 1997.

Your SDL does have several diagnostic capable modules... the EDS, SRS, and automatic climate control modules can give blink codes to help you figure out why they are grumpy.

What are you attempting to do?

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.