1994 Volvo 850T5 Motronic Diagnostic not working (previous owner may have disabled)?

Folks, I think the previous owner disabled the diagnostic port on my Volvo 850T5 (why do I think this?: Because, I asked if he had any check engine lights, and he said yes. He then said he took it to the shop and had some sensors changed...but when pressed he could not tell which. This was a year ago). Recently, I have had to diagnose some issues, but had to do it the old fashion way because I can't pull codes form my ECU...and MIL is not working (I figured he may had pulled the bulb...but I didn't feel like taking off the dash to check it at the moment.

The question is: How, and what can someone do to disable the diagnostic port on a 1994 Volvo 850T5 (ODBI) -- beyond pulling the bulb?

I speak from Canada, where the OBD rules phased in at a different time, but I'm pretty sure a 94 only has flash codes. Thats certainly the way it is here. Right front corner of the engine compartment, there is a small box with A and B segments, a wire to plug in, an led and a little button to push. Take cap A off, plug wire into hole 2, key on, push button for a second and the led starts to flash. 1-3-2, for example, might be a lean code.

Matthews volvo site or Brickboard probably has a list of what all the holes relate to, and what the flash codes mean.

It's also possible, if you have the standard data link connector, that it doesn't speak OBD2. We have some single cam 1996 850's up here that were never certified for use in the States, and while they have the connector, it speaks gibberish to a US based scan tool. We didn't demand OBD2 until 1997. I could be out by a year, but the same theorey applies.

In reply to Streetwiseguy:

Yes. You are correct. That diagnostic box is not working. No codes can be delivered. Not even the 111 (no codes code)

The ODB data link connect doesn't work either, but I was expecting that behavior.

See if the little black wire is broken, and then check continuity on the pushbutton. Its not unusual to have to smash stuff around some to get the contacts clean after its been sitting.

I'm pretty sure you can just plug a wire into the socket and ground it remotely, too. Ground for the same amount of time you would push the button.

Found this, but it sounds like you know whats going on.

Robert explains.

In reply to Streetwiseguy:

Thank you very much...Yup I have check out Robert DIY already. The ports (box upfront with the jumper wires) have power, when I press the button the light lights up, but no codes follow.

Is it possible for the ECU to work, but the diagnostic functionality to be disabled/cut wires?

Try a different port. Maybe see if you can flash ABS codes. I can't see disabling the diagnostic port. Pulling the bulb out of the dash, sure.

In reply to Streetwiseguy:

Cool. I was able to pull a code from port 1, but no others.

Hummm?