95 Sonoma 4.3 ODB1 with ODB2 16 pin connector
I hope this helps anyone how has a 95 Somona 4.3. Mine has an ECM located under the dash , passanger side ( OBD1) but the diagnostic port has a 16 pin connector (OBD2) instead of the 12 pin (OBD1). You can still get the service codes from the "service engine light" using the paperclip trick. If your connector is populated like the one in the picture you can short pins 5 & 6 to get the codes from the service engine light The codes will be GM OBD1.Do this with key on but engine OFF!
I heard this is true with some of the 1995 GM's
from 1996 on, use a scanner