ck engine light/ po125 code

[lec265104]

Hello.....I'm new to the forum....Need some help....my 1999 4runner has 203,000 miles and runs well....check engine light came on....so i checked all the vitals....changed a filthy air filter..... and reset computer...a few miles later..ck engine light came back on....went to advance auto parts to check code....po125 came up.....double checked radiator and coolant etc.....any ideas? could the dirty air filter mess up a sensor?.....thanking u in advance for ur input.....Lou

[kball]

Now that you have a clean air filter I would clean the MAF sensor. Do a google search on that. Basically you get some contact cleaner and spray it on the little wires and clean them off. Don't touch them with anything though, just the spray.

IF that doesn't get rid of the CEL it's probably your Air Fuel sensor AKA: your pre cat O2 sensor.

How long has it been since your O2 sensors were changed?

[lec265104]

kball...i did remove the maf....sprayed it with crc maf cleaner....replaced it...reset computer...a few miles later the ck engine light came back on....i cant remember if the O2 sensor was ever changed....i know i didnt change it.....ill check on computer for the location of the sensor....am i able to clean it?

[kball]

You can't clean the sensor. If you can't remember I bet it's time to change it. They are designed to be good for 80K miles. Anything after that is gravy.

Find the part you need here:

http://www.densoaftermarket.com/cata....php?part=afrs

Then go to Amazon and they will probably have a decent price for you.

here's another link for finding part number

http://www.urdusa.com/More-Products-..._13/index.html

[lec265104]

kball.....thank you....is it easy to replace?....its the one before the cat?

[kball]

Yes it's before the cat. Depending on your truck you may have 1 or 2 cats. You'll have to look. If you have two it will be in front of the first cat.

[kball]

Sorry, yes they are easy to replace unless you have lots of rust. Then your nuts may crumble.. haha Get new ones at the dealer before you start if they are rusting badly.

[lec265104]

Thank you...........am i hurting anything by driving vehicle with eng light on until part gets delivered?

[kball]

The only thing bad it can do that I know of is make the truck run rich which could hurt your cat over time.

I wouldn't worry about it for now. If your gas mileage goes way down then you'll know you're running rich.

[lec265104]

kball......decided to run another scan on vehicle.....code P1130 and P1135 also came up with P0125....does this confirm what u were thinking about the AF sensor?

[lec265104]

i did find sensor...it was right in front of cat as u said....one connector...2 nuts....when I order sensor from amazon...will it come with new nuts and gasket....it doesn't say on their websight

[kball]

Originally Posted by lec265104

kball......decided to run another scan on vehicle.....code P1130 and P1135 also came up with P0125....does this confirm what u were thinking about the AF sensor?

Yes, all 3 of these codes point to the A/F sensor.

Originally Posted by lec265104

i did find sensor...it was right in front of cat as u said....one connector...2 nuts....when I order sensor from amazon...will it come with new nuts and gasket....it doesn't say on their websight

I believe they come with a gasket but not nuts. If yours are rusted I would go get some at the dealer.

Part #90179-08059

[lec265104]

kball......on the denso aftermarket site.......they dont have my part listed under AF sensors.all they hav are 3 listed all calif parts....but its listed under O2 sensors....i saw one that has my engine size.....it says exc calif...im assuming that stands for excludes calif......also upstream and downstream...im assuming upstream....I just dont want to get the wrong numbers.......i hav a 3.4 v6 engine 4wd can u assist...

[kball]

You have the V6, 4wd, 1999, auto trans? and 1 cat or two?

This
1999 & 2000 49 State 2WD & 4WD auto V6; Front = 234-4162 1999 & 2000 49 State 2WD & 4WD auto V6; Rear = 234-4162

If you have an auto trans and just 1 cat (49 state)

This

1999 & 2000 Cali auto, 2WD/4WD V6; Front: 234-9002
1999 & 2000 Cali auto, 4WD V6; Rear: 234-4153

If you have the two cat Cali setup. Even though you may have bought your truck (or it originated) on the East coast it may still have been a California spec truck.

[lec265104]

kball....i hav a 99 4runner....3.4 v6 auto 1 cat.......so mine would be the first one on ur list