This sucks. Check engine light has been on for a little while now, killing my gas mileage. I need to just order the friggin sensors

 

How much do they cost? How many 02 sensors are there anyways? I don't know much about cars.

 

I think we have about 4 in our cars? Not entirely sure. I know there are some pre-cat and some post-cat, I think so anyways....

 

exactly.
2 of each
spray some liquid wrench before removing the old ones
and you will have to pull up the carpet to disconnect the post-cat ones inside the cabin

 

Are your sure it is an O2 sensor? What was the code(s)?

If so, try getting them online. They can be had for less than $100.

O2 Sensors

Denso OE identical O2 sensor 234-1054 234-1054 Front $77.48
Denso OE identical O2 sensor 234-4204 234-4204 Rear $87.50
Denso Universal O2 sensor 234-1057 234-1057 Front $35.48
Denso Universal O2 sensor 234-4208 234-4208 Rear $65.85


here is the link for an 93 SC300 to
sparkplugs.com

steviej

 

In my experience, the cat back sensors last at least twice as long as the front sensors, plus they do not
negatively effect fuel economy even if they are worn. So you may wish to replace only the front sensors to restore fuel economy.

Hope your K&N air filter has not fouled your MAF sensor with oil. I believe I have heard MAF sensor oil fouling can also cause a check engine light and reduced fuel economy.

 

It wasnt the K&N air filter. The light was triggered well before I installed it.

I'm 99% sure I killed an O2 sensor from using some of the fuel system cleaner in my car. I've read that using it when you have excessive carbon buildup can cause the sensors to go bad, and considering my car has 184k miles on it, it was most likely that.

 

Oxygen sensors start to get lazy and gas mileage starts to go down after 100-125K . So by 184K they were due to be changed anyway. Oxygen sensors have to get real lazy to trigger the check engine light.

 

141,000 and no engien light here. my ford went 250K on the o2 sensors.

 

I was on the old time way of replacing them every 100K ..now I just just my scanner to do a O2 test and see what it tells me.

 

I believe that Toyota and Lexus uses an O2 sensor with two circuits having four wires. One circuit is for the engine management and has two colored wires. The other is a heater circuit that preheats the sensor and has two black wires. Usually when the O2 sensor is bad the preheater circuit has gone bad. You can pull the connector apart going to the O2 sensor and check the preheater circuit with an OHM meter. Put the meter probes onto the lugs of the two black wires in the connector. You should get some reading of maybe 8 to 10 OHMs? Anyway the reading should show something more than zero for a good sensor. If any one of the sensors is bad it will throw a check engine light code. Check all of them.

 

Thanks for all the help everyone!!!

 

I know my sensors all showed around 1.002 volts @ around 600 degrees on them at last test. I can test and let you know if you wish.

 

https://www.clublexus.com/forums/sho...hreadid=137797

 

the link provided look great untill the cutting was in order. junk...

Buy the correct sensor and no cutting is needed. Plus a Bosch sensor