So I bought a stock 99 10AE. It runs/drives fine. I have a 20 dollar OBDII to Wifi adpater and it connects to my phone and works great. No issues. I can read codes, see realtime info, etc.

I go to get the car inspected, the shop says the OBD II port isn't' working. We tried wiggling the connector, etc, but he says it doesn't work.

I go to another one down the road, same thing, they said it doesn't work on their machine.

But the wifi dongle does work fine.

Any ideas? I've got the 99 wiring diagrams but so far I haven't found that port on the diagram. I have a scope, volt meter, etc, so hopefully can find the issue quickly. I'm curious how it could work sometimes. That seems odd.

 

Well turns out my neighbor had a wired obd II port reader. We hooked it up and found that you can wiggle the harness and it flickers on/off. So something is going on with that wire or plug. No idea why this would be a problem, but at least it's reproducible now. I'll update when I get it fixed and know exactly what what happened.

 

Seen this before on like 2-3 cars. often it's a bad solder/connection on the back of the obd plug where the wire connects to the pin

 

My car had this problem. We used to be able to hold the connector for smog and it would work until finally one time, it wouldn't. I was able to pull pins out and sort of reform them. Only had a problem with a couple of the connections. Now it works like a charm. Might have to do it again in 10 years or so.

 

That was it. I did some troubleshooting but everything from the back of the connector measured fine. So I depinned one of them and sure enough, there was no preload on them. I bent them in so they would bite, put it back together, and now it is working on my neighbor's wired one just fine. So fingers crossed that holds up.

Also I was immediately blessed with 6 blinks from the airbag light. So I googled it and clock spring came up, and cleaning/reseating the connector. I accidentally hit the horn when messing with it and noticed it took a lot of effort to even get it to honk.

But anyways ended up unplug/re-plugthe airbag connector a couple times and the light seems to be off now.

Plan to swap the clock spring and airbag and wheel soon anyway, so hopefully it stays working to get it inspected.

FWIW if anyone ever needs to do this, google how to depin the obd 2 port. I thought I could tell by looking at it, but I was wrong.

 

I checked and the connections above the copper look poor, I'm surprised mazda did them this way. Would have never thought that.

Also what up? Long time no talk.

 

I’ve used these at work when wiring ABS or OE ecus: Elite.Citi OBD II OBD2 Serial Port ALDL Data Link DLC Repair Kit ODB2 w/Cover Cap for GM https://a.co/d/gtY8Tka

Probably better than a 25 year old connector.

edit: we’ll that link sucks, try this one: https://a.co/d/cH8wKpB

 

Ordered. Thank you for the link, I had not seen this. You're 100% right, as the 25 year old connector failed again when I took it in this morning. Still won't talk to their computer.

Frustrating, but the plug you linked should solve this. Should be here monday!

 

This worked. I bought this, wired it in, and they plugged into it and it passed!

Thanks Curly for the help!