northfacer581

check engine light just came on. ran the obd scanner...code po420 came up, o2 sensor. is this something i need to get fixed asap, what exactly is it, and about how much will it cost?

thanks fellas

waskillywabbit

iTrader: (-1)

MY CEL light comes on, triggered by the 02 sensor, at least 1-2 a day because I have an aftermarket header and had to move the sensor. Nothing to worry about as it only does it in 5th gear under strain, so I just downshift before it does it....dealer said it was nothing as the 02 sensor tested out good, just not getting the "right" flow in the aftermarket header...

What year is your rig?...that might help to determine if it is that big a deal or not....

northfacer581

i just bought sam brocks 4runner (ssbogger7)....99 s/c sr5 4wd 5speed 5" lift 33" mud terrains custom rock sliders (himself) flowmaster streetlocks...anyways, thats what it is...the o2 sensor was the only problem he ever had with it so i just need to know how soon i need to get it checked out and if its a big problem...and the check engine light is staying on

PirateFins

Wabbit check this product out. Thay make one for importsCasper Electronics O2 SIM it is an O2 sensor box for high flow exhaust modifications.

Buck01

Pirate

have you used the 02 sim? I have put an LC enginerring header and highflow cat and muffler on my 94 22RE. My CEL comes and goes ever since I addded the exhaust.
When I check the code it is a 71. Which I think is an EGR error. I have replaced the EGR and checked vacum lines all are good. Just wondering if this might just be a case of ECU miss reporting an error?

if you have used the 02 sim did it help your issue?

PirateFins

I have not, but my dad put one on his Jimmy after he put a high flow cat on and it got rid of his CEL.

Buck01

I was just reading the casper elec website. They have a forum there also. There seem to be several issues with this device. They may be from incorrect usage i don't know. From what I read ( and I am noooo expert here) this unit will only work on vehicels with two 02 sensors. A front and a rear and the device is used only on the rear.

My truck only has one 02 sensor. So I don't think this would help me : (

3.4v6

i had a o2 sensor prob a couple months ago. it got replaced beacause of warranty but 2 days later with the new sensor plugged in it threw a code again. then a buddy of mine and a fellow YT'r told me that i could have a loose ground. looked and sure as hell there was a loose ground under the intake manifold. that fixed it.

PirateFins

Went and did some reading myself. 99% ofthe problems are from the guys that have gutted or removed their Cat's. The guy justin reminds them it was not designed for that use. Mainly to get rid of p0420 which northface is describing. I didn't see one listed for trucks or runners but you can email them and ask. Casper

northfacer581

should i take it to the dealership and have them replace the sensor, or is it ok and doesnt need fixing...sounds like its nothing to worry about and that it cant really be fixed because of the supercharger situation

midiwall

A P0420 isn't necessarily the O2 sensor... "P0420 Catalyst System Efficiency Below Threshold (Bank 1)"

ref: https://www.yotatech.com/~corey/tech/dr_z_obd/dr_z.htm


There are two O2 sensors in the system, one before and one after the cat. Outside of other things, the two of them talk to one-another and figure out if the cat's doing it's job. I'm pretty sure that P0420 is saying the two sensors have been talking and are thinking that things aren't going well with the catalytic converter.

northfacer581

so is this something i need to get checked out? i know the previous owner had problems with the 02 sensor, thats why i assumed that was the problem.

midiwall

If you care about what a cat does (makes the air cleaner) then yeah, it's something you should have looked at.


if you _do_ need a cat, then check out these guys on eBay: (if this auction is closed, then click "View seller's other items" and find another)
http://cgi.ebay.com/ebaymotors/ws/eB...tem=7967772359


That's a high-flow cat from Magnaflow for $56 _SHIPPED_. That's a hella price. I bought one the other day, paid immediately with PayPal and it was on a UPS truck within 12 hours.

Highly recommended. (thanks to <96 Runner> for the head's up)

ssbogger

Yeh you need to get it checked out. It wont hurt the engine or anything on the car but if the sensor is bad it will make it slow. The O2 sensor measures the air/fuel ratio and send the info back to the computer to tell it how much fuel it needs to put in for the amount of air coming in. A bad O2 sensor will mess up this mixture, i think the default for the car is to make it run rich (more fuel) so as not to hurt the engine. You can get a cheaper sensor from a site online, not sure where though. The dealer will charge you out the ass for the repair. I think its something like 2-300 for the sensor then prob another 100 for install. You could do it yourself for under 110. Sorry that happened man.

midiwall

From URD USA which is a company that Gagdet and Brian Trager own:

http://www.urdusa.com/Merchant2/merc...tegory_Code=O2

4Crawler

iTrader: (3)

I run an LC header on my '85/22RE, and 2" free flow exhaust. I don't get any O2 sensor errors with a stock Toyota (Dneso?) sensor, but I will get the occasional error with an NTK aftermarket sensor. The facotry sensors has a longer "nose" and stick farther into the exhaust stream (the flange on the header sets the sensor farther away from the tube than the stock header would). I think the shorter aftermarket sensor sits more in the dead "air" in near the edge of the tube.

I think the EGR code 71 is related to the temperature sensor on the EGR itself. That error is something to the effect that if the EGR has been open for X number of seconds and the temperature of the valve has not gone above Y degrees, it is assumed that not enough (hot) exhaust gas is flowing in the EGR. I found I had to open up some of the EGR ports in my LC header, since they were partly blocked by the weld bead from the mfg. process and from the exhaust gasket at the EGR return port. I had to do this in order to reduce NOx readings for a recent smog check.