P0420 Code, Had 2 Consults, Need advice!

K

KnightFiyah

New member
Hey guys,

This is my first post here and I wish it was about how much of a 4Runner fanboy I am but it's me stuck in a tricky situation .

I have a 2000 Toyota 4Runner SR5 and it threw a P0420 Code not too long ago. I did a lot of reading about this mysterious code and a lot of people have had success with replacing the A/F or Front O2 Sensor. I thought this was my issue as well since I've noticed a massive drop in my MPG lately; I thought it was just a bad sensor causing the car to run really fuel-rich.

Anyways I take it in to a place that specialized in Japanese cars and the guy seemed convinced it was the Cat. I offered up the possibility that it was one of the O2 sensors but he said it was a very slim chance.

I wanted a second opinion so I went down to my local Toyota Dealership of Lake City (I'm from Seattle, WA) and went in telling them I just needed the O2 sensor replaced. A couple hours later the service rep comes out telling me they didn't replace the O2 sensor and that the code they pulled was telling them it was for the Cat. I asked if the technician had checked to see if either of the O2 sensors needed replacement and he said yes and also seemed convinced that it was one of the Cats. (I'm taking what he said with a grain of salt because I wasn't talking to a technician, just some guy that files paperwork and talks to customers)

Basically where the urgency in all this comes into play is that I leave this Saturday morning on a trip to Canada. I have an appointment tomorrow at the same dealership to determine which one of the cats it is so that they can try to get the part in on Friday to replace it. Both the massive decrease in mpg as well as the check engine light being illuminated has me on edge for leaving for a 3+ hour drive to Canada both ways but I've had these plans for a while so I'd really love to take my car there.

You guys are my last hope. I'm desperate for any kind of help or feedback you guys can provide for me in this short amount of time I have before I have to leave the country.

Thanks,

Harrison
 
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Honestly it looks like you done your research and already have your answer. I have the same issue on my truck. I replaced both 02 sensors and still had the code, meaning its definitely my cat. Its about a 60% chance its the cat, IMO, you just have to decide if you want to take a gamble or no. You can replace the 02 sensors yourself, takes about 15 mins and relatively cheap compared to a new cat. If the CEL disappears, the gamble pays off and you're good to go, it it doesn't you know its 100% your Cat.

KnightFiyah said:
Hey guys,

This is my first post here and I wish it was about how much of a 4Runner fanboy I am but it's me stuck in a tricky situation .

I have a 2000 Toyota 4Runner SR5 and it threw a P0420 Code not too long ago. I did a lot of reading about this mysterious code and a lot of people have had success with replacing the A/F or Front O2 Sensor. I thought this was my issue as well since I've noticed a massive drop in my MPG lately; I thought it was just a bad sensor causing the car to run really fuel-rich.

Anyways I take it in to a place that specialized in Japanese cars and the guy seemed convinced it was the Cat. I offered up the possibility that it was one of the O2 sensors but he said it was a very slim chance.

I wanted a second opinion so I went down to my local Toyota Dealership of Lake City (I'm from Seattle, WA) and went in telling them I just needed the O2 sensor replaced. A couple hours later the service rep comes out telling me they didn't replace the O2 sensor and that the code they pulled was telling them it was for the Cat. I asked if the technician had checked to see if either of the O2 sensors needed replacement and he said yes and also seemed convinced that it was one of the Cats. (I'm taking what he said with a grain of salt because I wasn't talking to a technician, just some guy that files paperwork and talks to customers)

Basically where the urgency in all this comes into play is that I leave this Saturday morning on a trip to Canada. I have an appointment tomorrow at the same dealership to determine which one of the cats it is so that they can try to get the part in on Friday to replace it. Both the massive decrease in mpg as well as the check engine light being illuminated has me on edge for leaving for a 3+ hour drive to Canada both ways but I've had these plans for a while so I'd really love to take my car there.

You guys are my last hope. I'm desperate for any kind of help or feedback you guys can provide for me in this short amount of time I have before I have to leave the country.

Thanks,

Harrison
Click to expand...
 
You should just replace the O2 sensor, it's cheaper then buying a new cat.
For me I just had a P0420 pop up on my truck and it was Bank 1 Sensor 1 O2 sensor (before Cat). I bought two O2 sensors from Rock Auto thinking I should replace both front sensors sense they tend to go out at the same time. Well it fixed the PO420 code but then I got a PO430 code. I used a OBDII and it said "PO430 - Check for clogged or damaged catalytic connector". Right away I thought I had a bad O2 Sensor so I got it replaced and now both codes are gone.

Buy the O2 sensor and replace it yourself, its simple to replace and a lot cheaper then taking it to the dealer. Good Luck!
 
The A/F sensor and o2 sensors are not forever parts. They wear out like spark plugs do with a life span of more than 100K for o2 sensors.

If you have a scan gauge/ultra gauge, etc, the device can tell you what the a/f sensors are putting out.

Even though you don't have the gauges, I agree with the above posts in just replacing those sensors as part of an overall maintenance to do's.
If you do replace the cats I would go aftermarket.
They are both cheaper than OEM and a theft deterrent if you park outdoors.
Good luck
 
First off, thanks for the speedy responses guys. This really means a lot to me.

I'll go with you guys and just replace both O2 sensors. So now I just need to 1)buy the sensors and then 2) replace them:

1) The closest place in the area is O'reilly Auto parts and they last told me (about a month or two ago) that they only had a Bosch sensor which as far as I know is not the OEM brand sensor. (I think it's Denso?) So it's probably just a Universal sensor that fits my 4Runner. I've read a few topics saying that OEM is definitely the way to go, and I would definitely prefer it as well, but for the sake of the trip I might just pick these up unless I can find a place that carries the OEM brand sensors on hand.

Let me know what you guys think.

2) I think I bookmarked 1 or 2 quick guides on doing this but it should be pretty straight forward? Just remove the old sensor and replace it with the new one?

Thanks again!
 
I can tell you the p0420 thug will trip telling you to replace the cat.....even if you have a brand new CAT. I'm having this code with a new magna flow cat and new o2s. I'm starting to think the "bank one" or "cat not ready" is really the computer saying "I really have no idea what's wrong" PS I'm getting 9.1 mpg with a p0420 that's hand my CEL on for 3 weeks now.


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KnightFiyah said:
First off, thanks for the speedy responses guys. This really means a lot to me.

I'll go with you guys and just replace both O2 sensors. So now I just need to 1)buy the sensors and then 2) replace them:

1) The closest place in the area is O'reilly Auto parts and they last told me (about a month or two ago) that they only had a Bosch sensor which as far as I know is not the OEM brand sensor. (I think it's Denso?) So it's probably just a Universal sensor that fits my 4Runner. I've read a few topics saying that OEM is definitely the way to go, and I would definitely prefer it as well, but for the sake of the trip I might just pick these up unless I can find a place that carries the OEM brand sensors on hand.

Let me know what you guys think.

2) I think I bookmarked 1 or 2 quick guides on doing this but it should be pretty straight forward? Just remove the old sensor and replace it with the new one?

Thanks again!
Click to expand...
I'd highly recommend OEM sensors.......and then get the codes reset.
 
OR just order the correct Denso units off of Amazon.....

I wouldn't buy Bosch anything.


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Yep that's what I ended up doing haha

He kept saying "Universal O2 Sensor" over the phone and I was like, "Do I really want to do this to my car?..." NOPE!
 
The P0420 code just means you need to smoke more weed. There are tons of threads on this... Get the good stuff from the dispensaries and everything will be fine
 
I'll smoke a bowl once I get my car stuff sorted ;)

I don't really want to start another thread, so hopefully I can still snag your attention.

Any suggestions on suspension improvement? Trying to get the best bang for my buck and I'm leaning towards new shocks all the way around unless there's something particular about 3rd Gens that I should replace instead.

Probably won't replace them before my trip unless I can get my hands on some solid shocks before Saturday.
 
infamousRNR said:
The P0420 code just means you need to smoke more weed. There are tons of threads on this... Get the good stuff from the dispensaries and everything will be fine
Click to expand...

Dang im surprised my runner hasent thrown this code from all the second hand smoke It gets when i wrench on it
 
Update!

I replaced the sensor and took a look at the old one:

IMG_1814_zpsrgsim2h8.jpg~original


Is this clear evidence of a sensor going bad?
 
Damn it. When auto shops do this shit it infuriates me.

Cat's generally DO NOT go bad on their own. Yes they have a life span. However 95% of the time an external sensor or engine condition is the cause of a Cat's failure. P0420 is nothing more than a symptom. Find the problem.
 
Diezel said:
Damn it. When auto shops do this shit it infuriates me.

Cat's generally DO NOT go bad on their own. Yes they have a life span. However 95% of the time an external sensor or engine condition is the cause of a Cat's failure. P0420 is nothing more than a symptom. Find the problem.
Click to expand...

Yeah I just drove from Seattle to Vancouver BC and back (~300+ miles) and my MPG jumped up to about 20, the check engine light hasn't come back on, and it's running like a champ.

Looks like it was the A/F sensor after all unless it takes more driving to trigger the CEL.
 
code advice needed here as well

I am a newbie so can't start a new thread so sorry about jumping on this.
My '12 4runner had the check engine light go on. O'Reillys gave me 3 codes
c1452, p0504 and 01604. any advice? car has been running fine and is maintained on a regular basis.
thanks!
 
You may have better luck in the 5th Gen section but here goes.

The first code appears (could be wrong) to relate to the traction control motor and a possible short to battery.

The second appears to relate to the brake lite switch malfunctioning.

Not sure about the third one.

Unless you know or know someone who can dig further, I'd take it to a mechanic you trust. Luck. :cowboy:
 
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