I had 'check engine' light on my RX350. After some inspection dealer told me that oxygen sensor needs to be replaced, so they placed a new sensor today (paid $420 for sensor + labour).

After driving the car for less than 15 kilometers, 'check engine' warning came on again, so I bought the car back to the dealer for inspection. This is what they told me:

"After replacing one of oxygen sensors, other sensor now receives a different information because they are related together. In order to fix the issue, you also need to buy 2nd oxygen sensor." That's another $420.

WTF? Can this be true? Honestly, I think they replaced the good sensor, so the bad one still issues a warning... Any thoughts?

 

This sounds fishy to me.
Is your car still under some kind of warranty ?
Is the O2 sensor by the emission warranty ?

 

Believe it or not, yes this can happen. I have seen it on the first generation board. btw, it`s probably the air/fuel ratio sensor, a more advanced version of the regular o2 sensor.

 

txt, the car was built in 2007, so it's out of any warranty.

 

It is good to know what the real code is. Go to Autozone or O'Reilly and borrow a code reader for free. Or you can linkly ask them to read the code for you. Sometimes the code seems to be O2 sensor related. But actually the problem is not caused by O2 sensor. This happens a lot.

As long as whether the O2 sensors are related. I doubt that. Each sensor reports what it measures to the control unit and control unit process that data. Unless the second O2 sensor is also bad, it doesn't seem to me that these are related especially if they are in different bank.

I haven't done anything for Lexus yet because my Lexus hasn't needed that. But I have done O2 sensor for other cars and trucks. $420 for replacing a O2 sensor is a lot.

 

The air/fuel sensor on the first generation for OE runs about $100 (part only) And that is cheap for the Denso OE sensor...

 

dcdyd, I live in Europe, Lithuania, we don't have Autozone or O'Reilly here... Moreover, we have the only Lexus dealer here, so they can ask any prices they want

 

That is really bad, man! Sorry I assumed that you live in the States. My next suggestion is to buy a cheap code reader from eBay and start doing some DIY if you want to know what is going on with your car. Those listed in eBay for $20 to $30 will do the job.

 

Well, I can borrow code reader from some guys, but I will need a list of error code meanings then. Is it available somewhere?

 

GOOGLE is our friend. Lots of site has OBD-II code description listed.

 

Here is one.

 

Here is a site specifically for Lexus.

 

Thank you!

 

find a reliable mechanic to do the job for you....good luck and keep us posted....

 

Guys from my local Lexus dealer are fu**ing idiots! The fault was related to gas cap (yesterday Check Engine light came on in 1-2 minutes after re-fuelling the tank) and today it went off after driving the car for several KM. If it was oxygen sensor fault, the lights would NOT go off without connecting a computer to the car (no matter if sensor works or not at the moment).