1994 volvo 850 obd1 diagnostic box replacement

winslow58 · Post by **winslow58** » 28 Jun 2014, 16:43

I have a 1994 Volvo 850 with over 200k miles, my obd1 box broke, I replaced it with a used one from auto junk yard, but it does not work, it's from the same year and model. What could be the problem?
How can I get a new replacement?

Post by **pkc303** » 10 Mar 2016, 19:00

Good question, what did you finally do?

firestarterpro · Post by **firestarterpro** » 11 Mar 2016, 05:12

I've replaced mine a couple times... (dropped sweat into it while i was checking codes)
As long as you plug it in at the bottom, it should work fine. No system reset needed.
Chances are you got another dud. I have one in my car from a 95 that had OBDI and OBDII, so the year shouldn't matter, as long as it has it under the hood by the washer reservoir.
I can go by a junkyard and see if I can find another and test it on my 94 to make sure it works, if you need me too.

Post by **pkc303** » 11 Mar 2016, 08:21

Ok. I'll look for the plug. So it is just a large connector?

firestarterpro · Post by **firestarterpro** » 11 Mar 2016, 15:50

I lied, there are three. Two big ones at the bottom and one small green one on the side

Post by **pkc303** » 11 Mar 2016, 16:44

ahh, the plugs are what are falling apart on my car. I'll need to replace them. Eventually.

firestarterpro · Post by **firestarterpro** » 11 Mar 2016, 19:58

On my cruise control, the wires were falling out the bottom of my plugs. I pulled them out, picked out the old rubber, then stuck em back into the plug. Used super glue to get them to stay in place and then rubber cement to fill in the gaps to keep them steady.

I'm not sure how bad your plugs are, but if you just want to check the code, you may want to connect the probe to the bare wire instead of through the socket [plug]. All it is, is a plastic box with the button. The two big plugs, at the bottom, should be active without needing to the plugged in. You only need to plug in the green one, so the light comes on.

Post by **pkc303** » 12 Mar 2016, 00:20

Thanks, I'll have to rebuild all of the connectors in the box. All seem shot.

My cruise control is inop. right now. Haven't checked the plug for it. Any guidance on where to look first? Checked vacuum lines already. Was about to start on electrical next.

firestarterpro · Post by **firestarterpro** » 12 Mar 2016, 05:09

The brake sensor (valve) on the pedal. There a button, the brake pedal holds down that keeps the cruise control active, until you hit the brakes. Sometimes it can get pushed back too far or knocked out if your foot slips off the brake pedal too many times or you accidentally kicked it.

This https://www.matthewsvolvosite.com/forums ... hp?t=23825 has a picture of it. Just read Ozark Lee's posts.

tysauce1986 · Post by **tysauce1986** » 25 Apr 2019, 20:44

firestarterpro wrote: ↑11 Mar 2016, 15:50 I lied, there are three. Two big ones at the bottom and one small green one on the side
FB_IMG_1457736565176.jpg

What is the third wire for? Mine doesn't appear to connect to anything and has plenty of corrosion.