[Scrapy]

I have a mystery check engine light in my 2007 Pontiac G5 Base. It comes and goes when it wants, when the check engine light is illuminated on my dash board, I can't seem to read the dam code.. The obd2 port in my car won't tell a code reader that my car has a code. Is there a way to trouble shoot the obd2 port? Or is there another way to read codes? The only thing I have done is replace/ upgraded my exhaust system. I replaced all components from the down pipe to the muffler and tail pipe. I have both 02 bung holes welded in, they seem to be connected.. The only thing I never bought to install was the resonator. If anyone can give me some advice, I would really appreciate it. Thanks

 

[melwff]

check the cigarette lighter fuse to see if it is blown, it powers the obdII port

 

[Scrapy]

I checked that. The fuse was blown.. As soon as I replaced the fuse the same fuse blew again while I was checking for power in my cigarette lighter.. I haven't been able to get code. Once I get code, I'll update this post

 

[melwff]

why were you checking for power in your cigarette lighter after changing the fuse? If you touched the center contact and the outer shell at the same time the fuse will blow.

 

[toolman]

What melwff said is correct. You should check out the inside of the cigarette lighter plug to see if there is anything in there. I've had a couple of circumstances where a power adapter fell apart and left some pieces in the lighter plug. They would cause the fuse to blow.

 

[tuppenyturtle]

Ive seen coins in cigarette lighters as well. Sometimes people dont notice and pop.

 

[Scrapy]

I have an iPhone car charger that has a blue light on it when it's plugged in. That's what I used to test the cigarette lighter plug.. It blew the fuse instantly.. Since then I have not plugged anything in and have got on the code p0420..

 

[shadow11790]

1) i would get a new charger if its blowing fuses
2) did you replace your cat when doing exhaust? p0420 is most def a catalytic converter code so something within your exhaust system either in the cat or possibly your rear O2 might not be reading properly

 

[melwff]

read this link concerning the P0420
http://www.obd-codes.com/p0420