No power to OBD II plug - Third Generation Forum

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No power to OBD II plug
Tuesday, April 05, 2005 10:49 PM
I just finished installing an engine in my sister-in-law's 98 Cavalier LS sedan. It's a 2.4 Quad4 with an automatic. Anyway, the install went smoothly, and the engine runs great, stronger than any automatic Quad I've ever driven. The only problem is what I assume is a residual check engine light, and our inability to reset it. The OBD II plug isn't powering up the scan tool (we've tried 3 different scanners), so we can't read or clear the code. Has anyone else run across this? What circuit does the OBD II get power from?

BTW, I found this car at a junkyard. The previous owner had blown the head gasket, and I had 6 months to work on it (My sister-in-law had a 6 month "vacation" imposed on her driving). When I started tearing into the engine, I realized there was water inside the engine, so I found a good used one online. That was just as well; when I reused the original intake on the new engine, I ended up with a huge vacuum leak. It turned out the PO had run the old engine so hot that it melted the intake manifold. The plug boots were toasted as well.

Re: No power to OBD II plug
Wednesday, April 06, 2005 8:21 AM
I had the same problem with mine. Check and replace the 20 amp mini fuse for the cigarette lighter and you should be able to read the codes then.

good luck
Re: No power to OBD II plug
Wednesday, April 06, 2005 7:24 PM
Isn't cigarette lighter the blue 15amp?


Re: No power to OBD II plug
Thursday, April 07, 2005 2:53 PM
No the cigg lighter fuse is a 20amp and is yellow. It can usally be found under the hood on GM vehicles. But if your OBD II port is dead this will be the fix.




Re: No power to OBD II plug
Monday, April 11, 2005 9:50 AM
The only fuse I've found for the cigarette lighter is a blue 15a in the dash fuseblock. That one's fine, and the cigarette lighter works. I looked under the hood the day I tried to get the codes read last, and all I found were the big blade fuses. All of those were good as well.
Re: No power to OBD II plug
Monday, April 11, 2005 5:23 PM
I don't know what to tell you. I know for a fact that the cigg lighter and the OBD II port use the same circuit. I guess I would start with checking power and ground at the port and start working your way back from there. When you finally hit power and ground, you would have just past your problem. Also, make sure all the metal pins are in the port.
Here's a diagram of the conector. Hope this helps.





Re: No power to OBD II plug
Wednesday, April 13, 2005 7:17 PM
listen to the man, i had the same problem a few weeks back..



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