00 needs new cats... help?
- Thread starter DanRC30
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Clemsonfan15
New member
You could just cut them off and put on a simulator. That would probably be under $200.
You could also get high flow cats.
You could also get high flow cats.
I just recently had the P0420 CEL code also which meant the cats were bad. I replaced the front o2 sensor and after 125 miles the CEL is still off. Might be worth trying before investing the time/effort of replacing the cats. I was able to get the denso o2 sensor off amazon.com for $120.
004Gunner
New member
I had the same issue and did the same thing after you mentioned it worked for you. It fixed my P0420 too. To the OP, I tested out my rear O2 and the resistance was in spec but I couldn't test the voltage without a diagnostic OBD computer.
TheDurk
Elite Member
If the resistance is out, it throws a different code anyway. I can graph the voltages with my BR-3, but I am either not smart enough to distinguish a degraded sensor from a bad cat by the voltage curves or it can't really be done, at least on the two-cat A/F-front/O2-rear systems. I could tell I had a problem, but not what it was. The front A/F sensors signal by current not voltage so the front signal is pretty flat. I just go by the rule that if the sensor is old enough (70K+) I'd rather spend $75 and try to keep my OE cat for as long as possible. I doubt whether the dealers can either. There is equipment to analyze the exhaust gas and be sure, but I don't think they usually do that. I would love to know--but not enough to go near a dealer service dept.
004Gunner
New member
I hear you. I don't think a dealership does, or even can do, half the diagnostics listed in the fsm. I agree sometimes replacing the sensor is the easiest and cheapest route.
004Gunner
New member
I thought it was just Cali. At least everyone always refers to it as Cali spec and the emission sticker on the hood only mentions California.
brian2sun
Elite Member
That's what I thought too, but why do the guys in NY, NJ, and SC have 2 cats? Makes me wonder if a few other states go by CA standards. Glad I can still pass smog in CA w/ only 1!
TheDurk
Elite Member
Separate Cali specs started in '98 and lasted until 2001. In 2002 all 4Runners had the 2-Cat system and there was no more Cali spec. During the '98-'01 years, Toyota sold Cali. spec trucks all over the US in unknown (to me, anyway) proportion. Bad news is, once your VIN is born Cali. spec, you are Cali. for life under Federal law. And advanced emissions states (like NJ & NY) expect you to pass the standards it was built to, and rely on the on-board system to enforce that.
TheDurk
Elite Member
Yep. FSM fix priority for P0420--Catalyst System Efficiency Below Threshold is:
1) Fix any other codes
2) Fix any exhaust leaks
3) Front O2 Sensor
4) Rear O2 Sensor
5) Dead Cat.
The only thing the rear sensor does is tell the ECU to set P0420. It has no other function.
Reality is cats are rated for 150K+, O2 sensors 70-100K +/-. But sensors are a LOT cheaper. Checking for leaks cheaper still. Rear ones last a little bit longer than front ones due to lower temps.
brian2sun
Elite Member
Thanks, good info.
Weird because we changed the rear one first I believe...
Where's the best deal on a new plug in replacement O2 sensor? I remember trying the ebay route and it didn't match. Had to return it and go to the dealer where I got raped. lol!
Where's the best deal on a new plug in replacement O2 sensor? I remember trying the ebay route and it didn't match. Had to return it and go to the dealer where I got raped. lol!
TheDurk
Elite Member
If your rear sensor is relatively new, then changing it probably won't help. I had the impression it was of unknown age.
In any case, I got mine from urdusa.com (Underdog Racing Development). They have the best info on the correct OEM Denso part number for each configuration of truck. (Warning: I usually post live links but when I just went there to get the URL my Avast anti-virus had a heart attack--Trojan warning. Not sure what's up with that, I was there a few days ago.) Their prices are pretty good, but with the correct Denso number in hand (make sure you have the right one) you can check Amazon (very good prices, LOUSY application info) and other places for a better price. Only use Denso sensors; Bosch are definitely not good for many people based on what I have read.
I don't know the actual codes it threw. My friend the toyota tech never told me...
I'm going to try changing the rear 02 sensor since we changed the front one and not the rear.
