1990 300E Code Reader Help?
 

My 16-hole diagnostic port doesn't seem to match the info that I've found for how to use a code reader.

#1 besides the contact sleeve in the hole, it has a black button below it
#3 also has a contact sleeve and has a red light below it
#6, 7, and 14 are the only other ones that have contact sleeves.
All the others are empty.

The instructions on my reader say that #1 is for ground (black wire) and #16 (red wire) is for power but it's empty.

Of the available holes with contacts (3,6,7,14) which will I use for power?

Is it correct for me to assume that I'll pull codes from the remaining 3?

Thanks,

AL

I don't have direct experience with this but CA spec cars used the light and button, 49 state cars did not.

Just connect power to battery, connection 3 is trouble codes for cis

If it has an led and button , hold down button for 3 seconds and count the number of flashes

Seems like 89/90 was the break point of having a real port and one that tests items like the infinitely important seat belt buzzer only.

CA Car owners: code reader help?
 

Calif. car owners. Any instructions on how to use the button and red light that's on the diagnostic socket itself?

Thanks.

CA car code reader info: solved
 

Per my local indi-mech, for CA cars with Black button and red light at diagnostic socket (below #1 and 3)

Key on w/ engine off
Hold black button down 4 seconds, then release
Count number of time red light flashes to determine error code
Repair issue
Reset by holding down black button down 8 seconds to move on to next code if present

System will only display one code at a time.
Reset only clears one code at a time.

Fault code manual for Mercedes...
http://www.mbslk.com/files/artikel/r170_fehlercodes.pdf