2000 tacoma cat problem

So i just bought a 2000 tacoma v6 5spd like a week ago. It has 124k miles original in pretty good shape. The check engine light came on and it reads p0420 which is a cat problem. I still have to get it smogged check i live in ca, which is now going to be an issue. It seems to me that they're bolt on. Is there anything i can to do try and fix them? If not where can i get a good cat? and since they're bolt on i imagine it shouldn't be hard to do myself. not looking to spend money at a shop. Where should i start? to my knowledge there are 2 cats on the v6 models should i get one only? need to try and fix this problem asap. should i try to reset check engine and get it smogged whats the chances it will pass? Any knowledge or tips helps thanks so much.

 

Oh god....... CA cats are expensive as shit iirc

 

yeeep

 

is there a good method to try and clean them or fix them before i go buying new ones

 

Get on www.car-part.Comand find a new one or register your truck in Maine and get an out of state license lol

 

Make absolutely sure it's the cats and not the sensor itself. Or even fuel trims. There's other possibilities. Most likely it's a cat. But replacing the cat and still having the code pop has happened before. So before spending the big bucks on cats that may not be bad, check everything. If you are not sure how to do the checks, it may be best to have a diagnostic ran to be sure. But the back pressure tester is a good tool to have and is pretty easy to diy. you could also try a laser thermometer. That can give a clue. But if they're barely out of spec it might not. Which can happen. They might be just barely inefficient and throw a code but not be completely clogged.

 

First off, welcome to the forum from a fellow CA member.

Second, to hell with CA smog checks.

These trucks seem to throw out P0420 codes for fun. I could be the sensor, it could be your cat is not performing up to snuff. It could be a dirty o2 plug. Mine was resolved during trying to resolve a no start issue.

https://www.tacomaworld.com/threads/no-start-engine-is-getting-spark-and-fuel-fried-ecu.387148/

During this i did a major sea foam treatment (sprayed it in the cylinders, intake runners, everything and left overnight), i also replaced the ICV, I had the interior out of the truck so i also unplugged all the connectors in the cab (including to ECU) and cleaned them of the grease packed in them with Deoxit spray. I also pulled the ECU for inspection, and the electronics specialist i go to found a capacitor blown off the board, which he repaired. After doing all this, i no longer get P0420 codes.

I wish i could say which it was that cured it. I would bet either the seafoam treatment, cleaning all the contacts, or fixing the capacitor on the ECU. Because the front O2 sensor is a wideband a/f sensor, most cheap scanners can not read the data coming off it. However the rear sensor is. You can still read the waveform off it with a regular o2 sensor.

All that being said. If you are able to, it might be worth your while to find a less then reputable shop in the shadier part of town and pay them a little extra to just 'pass' it. Back in the day before i did smog work i had a guy i would pay $200 each to pass my cars, but with the new 2014 STAR certified stations and equipment, its not as easy to cheat as it used to be. Pre 2014, it was common place with the gold shield stations, they do a lot more comparison checking to keep shops from doing hot piping on cars.

 

Yeah I was thinking about trying to find one of those smog places that I can pay to pass haha. But I also feel like I'm getting bad mpg maybe I'm not used to a v6 gas mileage but it seems a little too bad. Also can I take the cats off and clean them with any treatments? I just wanna try the least expensive things first. I've read you can clean them with soap and water.

 

Also can I take them off and clean them with sea foam? or is it best to put sea foam through the whole system

 

Seafoam actually helped my cat go out on its last lag haha

 

Welcome to the forum Auscal. We just dealt with this recurring P0420 code with a "new" '95 Tacoma 2.4 that my oldest son picked up. We tried clearing it and cleaning the MAF sensor, but the code came back. I did quite a bit of reading on it and determined a good gamble would be replacing the Air/Fuel sensor in front of the catalytic convertor. We also replaced the downstream Oxygen sensor (behind the CAT). We bought Denso units, new at RockAuto.com, for about 50 bucks each. No more P0420 codes; has been a couple months now.

I believe Toyota recommends these sensors be replaced at the 80,000 mile mark. Do some online searching re Tacoma oxygen sensors and code P0420: on these Tacos, a catalytic converter code does not necessarily mean the CAT itself is bad (regardless of what some emissions specialists may post online!

Let us know how this turns out for you. These forum threads are a great resource for other owners that may face similar conditions.

 

Couple more things: my son's truck started its life in California so was CA emissions compliant at one point. I know there are some very $$$ CA Oxygen sensors (IIRC $150+ each) available from the dealer. We took the chance on the RockAuto Denso units and they seem to work just fine - no more codes and it passed WA State emissions after we made the repairs. YMMV of course.

You also asked about resetting the code and trying to pass emissions. Be aware it takes a few driving trips after resetting the OBDII codes before the OBDII system will be "ready" to be tested by your State Emissions station.

 

The Denso is the OEM replacement for the wideband sensor. Don't go with universal type sensor, they are garbage. The sensor uses the oxygen content of the cable for atmospheric reference. When you crimp it, it will restrict the gas flow in the wires. If you solder it, the sensor will not work at all.

 

okay thanks so much guys, ill probably try and replace the o2 sensor, since theres 2 cats on the v6 models should i replace both o2 sensors at the same time? do they fit the same?

 

Two different sensors, the front is a wideband sensor. There is no need to replace sensors unless you know they are bad.

 

I replaced both sensors, though some of the online readings suggested the front sensor is the more common culprit. According to the Toyota Repair Manual, Code P0420 indicates, "Catalytic System Efficiency Below Threshold (Bank 1)". It suggests as cause these trouble areas (in order), "Gas Leakage on exhaust system; A/F sensor; Three-way catalytic convertor".

That tells me that unless there is an exhaust leak, the next likely culprit is the Air/Fuel ratio sensor (commonly referred to as the front oxygen sensor).

The sensors are different, though they look the same. They go in the same, i.e., nuts on studs and an electrical connector. When you do the job you may find the original nuts so rusted they are hardly discernible. On my son's truck the nuts had rusted to a tiny metal ring holding the sensors on.

 

okay, so my best bet it to start with o2 sensors, I've been looking at cat convertors and its about 400 bucks for both or even more. so probably best to start with o2, thanks guys.

 

does anyone have links to both sensors? I can only find the downstream one for 2000 v6 models on rock auto.

 

It's on the Rock Auto page under the 2000 Taco, 3.4 parts, "Emissions, Oxygen Sensor". The sensor numbers are 2349001 (auto trans) and 2349003 (standard trans). The listing is 12th up from the bottom, both are Denso units.

 

if its a p0420 the rear 02 sensor would be the culprit that's the sensor that monitors the catalytic converters. I had a reoccurring p0420 code even after replacing both bank1 and bank2 sensors and was pretty much resigned to get new cats, I kept turning off the check engine light with my OBD meter eventually after quite along time the p0420 went away and has not returned(lucky?) but I think the computer has to get used to the new sensors(my guess) so it kept setting of the check engine light,only after a few drive cycles without occurance I haven't had the light come back. so after replacing the 1 and 2 sensors be prepared to see the Check engine light come back, keep turning it off with a OBD meter if you have one eventually it might stop, I was resigned to get new cats after running down all other possibilities, I am quite happy that the light went away.