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O2 Sensor bad

1989 toyota 4runner. O2 sensor is bad and has the check engine light on. No need to spend $100+ on the sensor. Is there a way to disable it so the light goes off?



Wha? Grrrrr

If it is the upstream sensor, this will cause the truck to run poorly and get bad mileage. Sometimes the mileage drop can be 30-40% based on personal experience. You will pay for the new sensor in just a few tanks of gas. Besides this, the truck will also run worse and have less power, all while getting bad mileage.

You can ignore a downstream sensor sometimes. That can indicate a bad sensor or the cat is failing.

Also, you will fail inspection if there is any kind of emissions test in your area if you don’t fix this.


Can you explain why there is no need to spend money on a new oxygen sensor?

I understand that maybe you live in a state with no emissions testing . . .

But even so, if the oxygen sensor is bad, the engine won’t be operating at optimum efficiency

No emmisions test here. They dropped it a couple years ago.

Why no need to replace it?
I figured it was for "passing the test"
My bad. I know.
Does it effect gas mileage?

The O2 sensor adjusts the fuel trim. When the O2 sensor fails the computer goes into a default value for the fuel trim. This default value enrichens the fuel mixture because a lean fuel mixture would cause the combustions temperatures to increase which increases NOx emissions. So the engine will use more fuel with a defective O2 sensor.

By the way, you can get a new O2 sensor from Rockauto for as low as $35.00.


No rockauto here

“No rockauto here”

please explain . . .

I bought mine from WWW.ROCKAUTO.COM (They are online) for my '92 Toyota Celica for $45. Had it in 3 days with standard delivery option. It immediately passed emissions.

Plus shipping to alaska

The cheapest I cam find in town is $80 its a universal.

Do i need a special tool tp get the old one out?

You don’t need a special tool to replace the O2 sensor. The O2 sensor in your vehicle is a flange mount type held on by two bolts.


If it’s known for a fact that the O2 is really bad then my vote is for fixing the problem.

While I don’t fool with eBay much anymore, you might check there for an O2. Odds are you can find one on the cheap with free shipping due to the glut of listed parts on that site.

Its a gamble. Guy had the engine rebuilt said he replaced every sensor with the exception of o2. Engine light is on and diagnostic on this old girl takes time. Napa ect dont even have the tool to do it


Do NOT get a universal oxygen sensor

I’m talking about those sensors in which you reuse your old connector

Get a “direct fit” sensor

I would stick to Denso, since they are the ones who made it for Toyota in the first place


Napa going to have Denso I wonder?


In my neck of the woods, Napa stores usually stock Denso parts

$109+ shipping out of Wa. at napa for Denso

Im going to do a little online reasearch

Amazon $47.00 free shipping