warriors_03

Ok, so I have been getting the dreaded P0420 code off and on since Christmas, and it popped on again last night on the way to a graduation dinner. After researching, I am still wondering whether it is the oxy/AF sensor(s) or its actually the cat...I had it diagnosed at the stealership as the cat, but I have a hard time believing its the cat since I had it smogged in October and it hardly had any emissions coming out of it. The tech at the smog shop even complimented me on the low levels from this thing. So this time I took down all the freeze data from the scanner at autozone.

P0420 - Catalytic Efficiency under threshold.
RPM: 1944
38.0% Load Value
Coolant 188 degrees
87 degree intake temperature
3.1% Short Term Fuel Trim 1
14.0% Long Term Fuel Trim 1
-100.6 Short Term Fuel Trim 3
-100.6 long Term Fuel Trim 3
49 miles per hour
Fuel System 1: Closed

Does anything here mean anything to anyone (a tech??)

Thanks,
Mark

DeathCougar

iTrader: (23)

A tech reads the exact same thing you read. It will either be the O2 sensor, or the cat. I would check the o2 sensor, and see if its within spec (how to do that would be outlined in the FSM and no i dont have one for a 2000)

If the o2 is out of spec, replace it. If the Cat is bad (usually not the case) it will be quite a bit more $$$ to fix it.

Fink

https://www.yotatech.com/forums/f2/d...runners-67521/

Check that link out...maybe it will solve some issues for you.

First question is, do you have one cat or two? If you have two...that is going to be a PITA. I had to remove a cat, replace it and then install one of URD's Rear O2 Sensor Simulator's. After that I was fine.

Read that thread and let me know if you have any more questions.

Fink

BigBallsMcFalls

change your rear o2 sensor

power cycle the ecu

pattycakes77

iTrader: (2)

i had the 420 code about a year ago, had the techs scan it at the dealership i worked at and the readings showed that the O2 sensor(s) was working within spec. the tech said he'd clear the code and if it came back on i would probably need to replace my cat. well, it's been a year and no CEL since. i priced out some high flow cats and they are fairly inexpensive, O2 sensors are a little more. i don't live in a state with emissions though so i don't know how an aftermarket cat would affect that, and yes i've heard that the dual cats are a pain as well.

perhaps some one can use a scan tool to see if your O2 sensor(s) is working within spec and then you'll know if you need a new cat(s). my $.02 at least. good luck

toytech76

They have had problems with the factory dual cat setup. I would replace them both

mt_goat

I have a dual cat ECU but just run one cat. I was throwing P0420s every other day until I installed this:
http://www.urdusa.com/product_info.p..._id=1230100014

No more P0420.

warriors_03

Yeah...its a cali spec vehicle in cali, so I have to abide by all the smog crap...or the smog police won't let me drive my rug...and that would be a sad day...

mt_goat

Thats too bad, could get expensive if your cats are bad and you try to stay with OEM cats. Unless you happen to still be under the fed emissions warranty, I think its like 8 year or 80,000 miles IIRC.

BTW with the URD sim hidden well up under the dash, I don't see how the smog police would ever know about it.

BigBallsMcFalls

change your rear o2 sensor

toytech76

if its bad replace it but dont throw parts at it hoping to get away with a cheap fix