Driving last night and after being on the road for about 20 minutes saw that the
check engine light + the VSC Trac + VSC OFF lights came on. They weren't ON when I started the car.

Last Feb 2008, these lights came on and I ended up replacing the charcoal sensor.
Now, a little more than a year later, they are back on again. If we rule out the charcoal sensor, what else could it be?

I make sure that gas pumpers don't overfill my tank to burn out the charcoal filter and I checked the fuel cap.

I'll pull the fuse later today and reset the battery and see if the lights come back. Might stop by AutoZone to hook it up to the machine to get the number code for this first.

dont you just love those lights? ive seen them too many times but its useually cause i broke something trying to do things i read in here lol! so for me the common problem was the gas cap it took a couple days for it to shut off by itself, the MAF, i broke it trying to clean it, one time it pulled up my idle control valve was bad, i poored some injector cleaner in the gas tank and some how it shut off almost immidetly, um ive heard a bad Cat can set those lights off, other than that thats all ive had experience with. Ive been check engine light clean fir 3 snd a half weeks, im never touching anything electrical again

I am having the same problem. The light went out after I disconnected the neg battery terminal but I think the light comes back on after about 35 or so miles. I have heard the trick with the gas door, but why would it effect the stability control?
Anyone have answers? There are probably mulitple solutions and/or causes to this...

The VSC lights have nothing to do with the problem. The combination of CHECK ENGINE and the 2 VSC lights (from my understanding) refers to gas/air problems.

I took it to a car care place and they plugged in the OBDII and I got code P1135 (the machine also said gas/air flow mix sensor). I haven't taken it to Toyota yet. They would be able to get more specific. I added STP fuel injection cleaner, but that didn't do anything and I still need to pull the battery/fuse and see if that does anything. Last year's charcoal filter sensor cost me I think around $600.

I don't know if it relates to my lights going on, but a week prior, I had to remove the battery so I could replce the front headlight. The lights came on a week after.

P1135 Every time I've seen that code it was the front AFR/O2 sensor Give me a little more info about your truck (year, california edition, etc...) and I can give you a part number, or you can look it up yourself at http://www.underdogracingdevelopment.com/ that is the cheapest place I have ever found for AFR sensors.

Mine is a 2002 toyota 4runner Sport. I live in NJ, so don't think it conforms to CA emmission laws.

Is this part as laborious as the charcoal sensor? They said that it was expensive cause they had to take so many parts off the car to get to it.

You need part #234-9002, all 2001-2002 4runners meet california spec. installation is a piece of cake, it takes one 12mm wrench, remove two bolts, unplug the connector, repeat in reverse order...

AFR Sensor


Connector you disconnect

Thanks!

Is it under the hood or under the car?

not really sure from the photos.

Is there another place or machine that would narrow it down to this part as the one that needs to be replaced? Maybe take it to a gas station?
If it's this easy to replace, I just want to verify that it's this part and not something else.

It is under the car, on the passenger side. I don't know of a machine that will test an AFR sensor, but every person I know that has ever had that code, a new AFR sensor fixed it. After a quick google search you will find that pretty much any toyota with that code is fixed with a new AFR sensor. Good luck!

Thanks for your help!

i had this same problem a couple months ago, they thought it was the MAF and cleaned it but it didnt clear the code. Put it on some "smoke machine" and the problem turned out to be a cracked and leaking vacuum hose near the back of the engine. Replaced the hose and the code cleared.

No problem!

xStePheNyz - Did you throw the same code, or did you just have the christmas tree light up across the dash?

Hello....I don't remember the code number. But it was the same as described, the check engine along with VSC both on and off. My 4runner ran much much better when they replaced that hose. I think I spent about $200 for the testing, they did the smoke test after the code wouldn't clear which is how they found the culprit....stupid hose itself probably cost all of $1. I remember they said the hose was located at the back of the engine. It is a vacuum hose. Maybe worth just taking a peek and seeing if you see a broken or cracked vacuum hose back there?

you really just need a scan tool that allows you to watch the output of the sensor.

True, I guess I assumed that he wouldn't have access to one, I don't know what auto zone lends out as I have a Scan tool. If you're lucky they might have a Genesis or something and you could check the output of the AFR.