- theRanndom wrote:
- So I recently changed my headers back to the stock header after getting multiple P0420 CEL. I changed the gasket to a brand new gasket and put the stock header back on drive for a couple days only to have the code throw again. The only "mod" I have left on the car is a catback exhaust after the long pipe. Any idea on what would he causing this? I have some diagnostic info if it would help
hmmm.. have you reset the ecu after the multiple p0420 codes? You can do that with an obd2 scanner, or disconnect the battery and wait 10min then reconnect the negative cable back onto the battery. That should eliminate the codes.
That's the only thing I could think of, or the cat is bad.. Odd that we're getting a lot of people lately on the forum that are having a p0420.. and it all relates to headers.
The other thought is the gasket you used, was it aftermarket? The aftermarket isn't known for its quality lately. Been a sad slow down to the lowest cost. I'd reset the ECU first, see if the code comes back before we blame the gasket or the cat.