Does an '85 W123 have an electronic diagnostic port?

I ask because I wonder about this small black cylindrical part near the driver's side fender. The cap screws off, revealing a round outlet with several electrical ports. It's about the diameter of a 50-cent piece or so.

It's labeled with the Mercedes emblem, the part number, not sure what else off hand.

If it is a connection to plug in a diagnostic tool, are these devices available to the home mechanic? Worthwhile? Any other thoughts?

__________________
___________________________
1995 E320 (2009 - current)
1985 300TD Turbo black (2007-current)
1983 300TD Turbo red (2008-2009)
1972 280SE (2004-2007)
1977 300CD (2003-2004)
1976 240D (1999-2003)

Seriously doubt it. Send us a picture. Trace it out.

The reason there is no diagnostic port for an 85 300D is because there is no electronic computer and no electornic sensors to feed it information.

Unlike a gasser, there is no AMASS or Throttle positioner or MAP or O2 sensor which can be used to postulate diagnostic info. Half of the brain of the 300D diesel is mechanical --the IP Pump. T

The other half of the brain of a 300D is gray matter. Part of that outputs CHC--cold hard cash--and pays to get it fixed. The other part uses Tools and posts on this Forum

That is a cap to cover the plug end of the tach sensor. On '83 and older engines, an amp screwed in and sent the signal to the gauge. Newer models used a different system. I don't know of any diagnostic tool either.

__________________
83 SD

84 CD

Thanks -- that makes sense. I couldn't figure out why there'd be something to plug a computer into.

__________________
___________________________
1995 E320 (2009 - current)
1985 300TD Turbo black (2007-current)
1983 300TD Turbo red (2008-2009)
1972 280SE (2004-2007)
1977 300CD (2003-2004)
1976 240D (1999-2003)

is in 1985, computers uhhh werent really proliferated. A laptop was a dream and a a desktop was like a Mainframe abou the size of your car

Now thats just exaggeration. 1985 is when my dad spent $5,000 on his AT&T PC6300 desktop computer. It was quick for its day but it wasn't THAT big.

(Not my picture)

On my 85, I pulled off the cap. looking in the holes, I can see pins 2,6,7,8, & 9. have the brass female ends. so maybe it is a place the dealer plugged in some sort of a diagnostic meter. the grey from the crank hooks in from the bottom. and there is a black wire out the bottom that goes into a wire bundle going towards the fire wall.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Possibly related, as it appears to be a black box...

85 300D passenger side footwell, right bulkhead. I find a plastic trim plate about 4"x6", which, when popped out, reveals the mysterious black box and what looks to be a sensor or relay, also in black.

Any idea what this might be?

Thank you.

__________________
FRANKNBENZ

1985 300D "Old Blue" 265,000 (parts car )
1985 300D "Gray Ghost" 245,000
1985 300D "Silver Bullet" 160,000
1975 914 VW/Porsche "BC Car" 125,000
2010 Prius "Shocking!" 60,000
Text Message only: 301-728-1115

Anything is possible, psot a pic!