: Getting a P0420 code



KING03
07-08-11, 05:16 PM
Had the check engine light come on the other day and i'm getting the p0420 code, Car has no mods. Can it just be failed cats?

CancerJCC
07-08-11, 05:25 PM
Had the check engine light come on the other day and i'm getting the p0420 code, Car has no mods. Can it just be failed cats?

Yeah or just a failed o2 sensor which are a lot cheaper. How many miles and what kind of driving do you do with it? (I.e short trips to the store or long trips where everything comes up to temp).

I would start at the rear o2's first if they are original with any kind of mileage then go from there.

KING03
07-08-11, 08:04 PM
Well i just bought the car a couple of weeks ago with 74,000 miles. I dont drive it hard at all. I called the dealer and they said since its under 80,000 they will look at it and if its the cats they will replace them for free, but if its not i will have to pay the 125 diagnostic fee, so i am trying to see which is the best way to go

catch2otwo
07-08-11, 08:10 PM
My car had 58k miles when I bought it earlier this year. Same CEL popped up. I had scanned at home first and then brought the car to the dealer. They diagnoised it to be a bad cat. Replaced under emissions warranty. You can always swap 02 sensors first to see if you pop a different code. If it doesnt then you know its the cat that is bad.

KING03
07-09-11, 02:41 PM
when you say swap sensors, do you mean swap the before cats for the after cats?

darkman
07-09-11, 04:12 PM
You can swap the pre-cat sensor on the driver's side with the pre-cat sensor on the passenger's side. If the problem is an O2 sensor, you will get a diagnostic trouble code of P0430, which indicates the error condition has changed sides.

GDPossehl
07-09-11, 04:19 PM
For those beyond 80k with this code or problem, now may be a good time to go with some long tube headers with high flow cats. :)

JFensty
07-09-11, 06:23 PM
I get that sulfur smell alot but never get a code. V has 110,000 on it and runs great. Looking into ltd and high flow cats.

catch2otwo
07-09-11, 07:52 PM
when you say swap sensors, do you mean swap the before cats for the after cats?

Read below darkman has it right. It may be a little work but better then the dealer telling you.


You can swap the pre-cat sensor on the driver's side with the pre-cat sensor on the passenger's side. If the problem is an O2 sensor, you will get a diagnostic trouble code of P0430, which indicates the error condition has changed sides.

KING03
07-09-11, 08:42 PM
awesome i will try that out this week, and take it from there

darkman
07-09-11, 08:57 PM
awesome i will try that out this week, and take it from there

If you do not have one already you may want to pick up an O2 sensor-specific socket/wrench/tool which can make removal with the wire in place easier.

KING03
07-10-11, 03:30 AM
whats the part number on that?

darkman
07-10-11, 09:28 AM
http://www.summitracing.com/parts/WMR-W1267

Almost any autoparts store will something simiar.

RADEoN
07-10-11, 02:50 PM
darkman is my hero