Today I installed a cat back exhaust system (and a drilled out spark plug defouler) and it threw a bunch of new engine codes at me. Originally I had one code (P0420) and I decided to try the spark plug defouler on the downstream O2 sensor while I had the car up on a lift. The exhaust system is made for a 2.2L Colbalt but the hangars and the flanges are the same so it hooked right up. The current codes I have are P0030 (HO2S heater control circuit bank 1, sensor 1), P0036 (HO2S heater control circuit bank 1, sensor 2), P0102 (Mass or Volume airflow sensor 'A' circuit low), and P0443 ( EVAP system control valve 'A' circuit (the exhaust might be pinching a wire to the evap system, it's pretty right at the bend over the rear subframe)). I believe the P0030 and P0036 are because of the heated O2 sensors not working with the defouler. But I have no idea about the P0102 code. I will admit the cold air intake is cheap and is not perfect but it was functioning fine before today. The main issue im having is the transmission is shifting early now but I believe that's cause by the P0102 code

 

The P0102 is a MAF sensor code,

https://www.obd-codes.com/p0102

could be caused by a dirty or oiled air filter.

 

Its defiently not a dirty filter as I just installed it. However it is a 3 in cone filter instead of a normal 6 in cone filter. Today I'm going to clean the MAF and swap on a bigger filter to allow for more airflow. I appreciate the response Oldblue!

 

You blew the EXH fuse, #33 under hood.

 

Can I ask why you think i blew a fuse? I'm just confused is all

 

also litteraly just checked and you are correct. The 10 amp fuse it blown. How did you know this?

Update: I replaced the fuse and it blew again. I would assume that the fuse is blowing because of the defouler I installed.

 

Quick Update: I cleaned the MAF and replaced the 3 in air filter with a 6 in air filter and nothing seemed to change. I still have all the same codes as the original post. The transmission is still shifting early with each gear.

 

Gotta ask.
What kind of snake oil is a "drilled out sparkplug defouler" ? And why do you need one ?

 

I knew it because that fuse controls all of the modules that the codes refer to.
The fouler has nothing to do with short circuits. There is a wire shorting somewhere involving one of those modules, or one of them has an internal problem. I don't know what other mods you may have blindly tried. P0420 means your cat is broken.

 

its used to pull the downstream o2 senor out of the exhaust a bit. The downstream sensor was throwing a P0420 code telling me my catylitic conver is bad. Basically just tricks the sensor into thinking the cat is fine because the sensor isn't detecting the combustion cycles. Or something along those lines, I'm definelty not a mechanic though