Scangauge 2 broke my OBDII and is causing problems

Hi all,

I have been battling an odd problem with my 2000 2.7L Tacoma for about a little over a month now. Today I was able to determine what was causing the problem. It turns out that my scangauge 2 melted two pins on my OBDII port and melted the wires behind the port as well. You can see the carnage in the pictures below. The picture is after I separated the melted wires. It was much worse when I initially got in there.




Although the super weird part of it is that my truck will not start when the scangauge 2 is disconnected from the port. The temp gauge reads maxed out and it just cranks forever. Plug the scangauge 2 in, and the temp gauge goes back to normal and the truck starts. It seemed that the two melted wires had molded together and were possible contacting eachother. I did my best to separate them and make sure there is no electrical connection between the two wires, but the problem still persists.

Has anyone ever had this problem before? I checked the wires at the connections on the ECU behind the glove box to make sure they weren't smoked too, but everything looked ay-okay (see my picture below)

Here is a video of the problem in action. (Sorry for my uncoordinated one-handed maneuvers)

https://www.youtube.com/watch?v=ieyt39q3dNM

I was thinking of just splicing in a replacement OBDII port, but the fact that the problem is still present with the melted wires separated from eachother and the scangauge 2 disconnected, it makes me think there is something else going on that I am missing.

Any help you guys could provide would be awesome!

 

Might wasn't to check fuses. It is possible that the scangauge is completing the electrical circuit on pins that otherwise have no juice coming to them.

 

Disassemble the scanguage and show us pics

 

I have checked all my fuses like 100x over at this point. They are all good.

 

I wonder if the pins inside the truck's OBD2 port are internally shorting even if you cant see it.

My suggestion is you splice in a new OBD2 port. The only other thing which you could do is start pin checking all the pins for proper voltages but you will need a digital multimeter and a pin out diagram of the port. I believe pin 4 and 16 are power and ground. Sure enough it looks like pin 4 on your port is muckered up.

 

This

 

Ohm out the two pins as it sits right now. Just to make sure they're not shorted out within the obd2 molded plug itself. Then maybe ohm again with the scan gauge plugged in?

 

Did you happen to pull out the Ethernet cable from the back of the scan gauag and look for cuts in the insulation

 

Is there some sort of known issue with the scan gauge you're hoping to see?

 

I did check the whole cable and it was getting crushed at one point of the routing, but the scangauge seems to be operating as expected. And the cable was not cut or anything like that.

Just ohm checked the two melted pins. 10 mega ohms without scangauge connected. 400 ohm with it connected and truck running.

 

I meant the plug and wires, to check for a short

 

Regardless, you definitely have a problem upstream.
This one could be difficult to trace, check continuity across every dang wire

 

If you ask me there is a short and I'll bet you good money it is inside of the truck's OBD2 port. The scangauge plug is likely seperating the pins just enough to keep them from contacting at any one point. As soon as you pull the connector from the port they start touching inside slightly again. (Just a theory)

The Scangauge will not show any evidence of damage inside the unit. The reason this happened is simply due to the Scangauge pulling too much amperage out of the port over time. Similar to how a 55W headlight will melt a 35W headlight connector over time as well.

 

Your theory sounds promising. Im gonna head to an auto scrap yard tomorrow and try to wire in a replacement OBDII connector. I really hope that's the fix to the problem. If not, it looks like ill be pulling the dash apart and tracing lots of wires and testing with a multi meter.

 

In the automotive world we always address the most obvious issue first to rule that out as a known good item prior to delving into deeper and most often unnecessary testing.

Try that first and let us know how it turns out. Fingers crossed that it works out in your favor and that will be all you need!

 

It’s your new anti/theft device.

 

^^^^^^^^THIS^^^^^^^^^Alway's go where the weather is the roughest when working on a vehicle. and work your way back.

 

Terminal fretting, which caused the connection to get hot and melt. IMO this port should be used for diagnostics only vs. having something plugged into it 24/7

 

HIGHLY agreed. The port is simply not designed to see a constant connection.