P0420/p0301
 

I have an 04 with 105k miles. The car sat for 6months and this is when all my problems began. It had bad gas in it, so it was cleaned out. These things have been replaced in the past 2mo- battery,spark plugs,wires,& coils,ssv, downstream 02 sensor, radiator & reservoir. The car seems to be running good, but CEL is back on. I had it scanned and the 2 codes are P0420 & P0301. I am told the CAT needs to be replaced. So, I am having it replaced in a week. I'm wondering if this will cure the 2 codes and whether or not they are related. Any advice would be greatly appreciated! I don't know what else could possibly go wrong after this.Thanks.

check here https://www.rx8club.com/showthread.p...ighlight=P0420

To answer though- P0402 is a CAT failure code. P0301 is misfire. Deal with the CAT first. Inspect it on your own if you want (remove the front and have a peak inside)

I'll be replacing the CAT this weekend, so I'm hoping this is the last problem for a while. Hopefully it takes care of the 2 codes, but I will see.

I had the P0420 Code. Like Soldier said, it's Cat failure. I also have the P0301 one (Well not exact one, but for misfire on Cylinder 2). I'd check the plugs/wires/coils for that one

Is your cat still under warranty? It's covered for 8 year/100k miles.

p301
 

I just had the plugs, wires,& coils replaced, so I'm ruling that out.

no it's not under warranty, 105k miles.

i have an 05 rx8 do u thinik mines would still be under warrenty from mazda im from the uk u see so im unsure if the warrentys were extended to 8 years here also

The cat should still be under warranty 7 years or 130000kms In Canada dont know about U.S

^.........8 years, 80k miles in the US.

Think this is flat out wrong info whether in US or Canada. :spank:

re: P301

the eccentric shaft sensor (ESS) profile was probably not reset then or the ESS itself may need to be cleaned.

however, if the cat has failed it may also be blocked up, which can also create a condition that may cause this code

I just got a P0420 fault 2 days ago my cobb says cat threshold low, went to the dealer yesterday I'm at 83k miles so I'm out of warranty, so looks like I'm in the market for a new mid-pipe/exhaust.I'm pretty sure there is no way of knowing how long I have before the cat dies, but car is still running,planning to get mid-pipe/exhaust in the next few days.

NEWB question what is the worst that can happen if I don't get it fixed this weekend, and or cat goes completely out one me?

Don't want to risk it but the exhaust is in san diego and I wont be able to get it till saturday/sunday and put on monday evening.

Should be okay, limit driving if possible. Either that or just take it loose(off) and knock the guts out. Won't solve the cell, but will lessen any potential damage.....and not sure there would really be any in such a short time.