oliwer200

Hello All, I have been having an issue recently that’s stopping me from passing emissions. My car is throwing codes P2270 and P2273. The car has been running fine but I must mention that I have catless downpipes and CTS Turbo Cold air intakes. I have come down to the conclusion that the catless downpipes aren’t the reason for this because I do have a cat simulator running to the post flow o2 sensor sending out a good signal back. I recently got the P2270 code after a while of just having the P2273 code. I am stumped I changed the o2 sensors to no avail. I don’t know if the spark plugs could affect this code as they probably weren’t ever changed and the car has 66k miles. Maybe the MAF sensors need to be replaced ? I just want to know if anyone was having an issue like this before I start dishing money out on parts I don’t need. Thanks for reading any tips are greatly appreciated

C43Jay

Something is most likely going on with your simulator as one bank thinks its running rich and one is running lean for both rear o2s

oliwer200

The thing is that I only bought one simulator to make sure the P2273 code would go away so I had that code before the simulator on bank 2

bhvrdr

Simulators are 50/50. I tend to personally avoid them as the later model cars actually use the secondary "monitoring" sensors for active fuel trimming. I prefer to just tune out (calibrate out) the cel but not mess with the sensor itself. For emissions I wouldn't ever think to try and pass them without a functioning cat.

oliwer200

Tuning it out still causes the inspection to say that the o2 sensors are “not ready” for therefore resulting in a failed MA emissions test

bhvrdr

Correct, hence. ...
"For emissions I wouldn't ever think to try and pass them without a functioning cat."
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oliwer200

My bad my brains fried after todays work day skimmed through the reply everything was so much easier with my 2016 C300 I put a catless downpipe on there with a spacer and a code never appeared lol could pass emissions like if I had a cat the whole time and it wasn’t tuned I guess it was easier since smaller engine displacement

Josh.A.Hussey

Did you ever get this figured out?
I have modalworks fully enclosed carbon fiber intake to put on and some catless downpipes, don’t wanna throw any codes.