Ok so i bought a 2.5 Catted ZZP Downpipe and the CEL came on a day later I drove with it on for a month. And went to a Muffler Shop they told me I have to install my stock downpipe because all aftermarket downpipes throw codes.....Im really confused can someone help me Please.!! The reason why i bought this ZZP downpipe was because i get Flex pipe leaks every 3 months or so.

 

Take the car to autozone and see what the code is. That would be the only way you could figure out what is wrong.

It could not even be related to the downpipe.

 

yes check the code. i have a 2.5 Catted ZZP pipe and no codes for me. if its an O2 code, reset it and see if it comes back.

 

I did it says the P0240 code and could be large vaccum leak, engine oil leakeage, Engine misfire or Catalytic Converver failed. But the guy told me since its aftermarket Converter it will throw a code

 

p0240 or p0420?

 

P0420 sorry

 

ok well you can get hptuned and block the code or get one of the defoulers that pulls the rear o2 a lil bit out of the exhaust stream
it's throwing it cause the rear o2 is reading too close to what the front one is so it thinks the cat isn't working lol

 

Throw a vacuum gauge on the motor, if nothing is found on there, then its the rear o2 sensor, think about it, you put a high flow cat on the car, the sensor is used to reading a clean exhaust, now that the flow has been altered, it doesnt know what to do.

 

Oh ok thank you guys ill try that and see hopefully it works

 

Vibrant Oxygen Sensor Defouler - Universal Exhaust Items

 

So i can pass Inspection with the defouler and is it a for sure fix do you know

 

most likely that'll solve it high flow cat is give or take if it's gonna throw the code....cheaper than 200 for a tune lol.....you could try to put some washers inbetween the bung and the o2 sensor too doubtful that that'll pull it out enough though

 

oh ok thanks ha