Just for info:
A misreading O2 sensor will cause this code.
You replaced one O2 sensor.
What about the other one?
You have two O2 sensors.
One for each bank so if one of those O2's are misreading, it will throw the 606.

I also asked earlier if you can see the impedance on both O2 sensors.
I'm just trying to eliminate a bad O2 here.
Not saying your flash or some other component is throwing the 606 code.

 

Sorry I have a tendency to add more information to my posts than necessary. I replaced the driver side o2 sensor and the code disappeared but left me with a sole error code p0606.

 

There are plenty of real codes for leaks and o2 sensors. Why is p0606 being associated with o2 anything?
You read this?
https://www.engine-codes.com/p0606_toyota.html

 

I think the reasoning is that the p0606 code is coming up and usually it's not the PCM and its sorta a false positive that's associated with o2 sensors and the such. That's as much as I've gathered from everyone's input.

 

I would replace the other O2 sensor at this point if you find no exhaust leaks around it.
And if the 606 comes back with both 02 sensors replaced, ECU would be the only one left.

 

​ Being a mechanic myself, you should always keep in mind that codes only point you in a direction. Say you have a misfire code for cylinder 4. This code is pointing you to every circuit and every physical function related to Cylinder 4. Say you have a heater code for o2 sensor bank 1, sensor 2. This code is pointing to not only the heater in the o2 but any part of the heater circuit, ie wiring, connectors, and the heater itself. Codes point to the circuit involved.

I would be more then happy to do some research on your code. I have access to Alldate and Identifix.and seeing as I am a new Lexus owner I suppose it would be in my own best interests to look into it anyway. 😉 P0606

 

The gist of it. Its either a/f sensor, wiring or ECM. Keep in mind many manufactures require an OE sensor to fix the problem. Aftermarket will not work.
Pictures are clear on my phone!?!? Lol

 

Thanks a lot Shawn Bailey for the helpful insight! Your pictures are clear thanks!

EDIT: Problem finally solved, system picked up the other sensor that I didn't replace was acting faulty, replaced and no more engine codes p0606

 

guys this is an old post I know but i have a question, anyone of you flashed away the first set of o2 sensors and cats? I am not in the US, anyways I am asking here because ou guys do more stuff with the IS than the LS. So the issue I am having is 1st set of cat delete (LS has 2) and 1st set of o2 sensors. The cat has been removed.. the 02 sensors have not. they are still attached. I has the ECU flashed supposedly to delete as stated before and it was running ok, then I start getting P0606 codes once in a while with check engine light but it comes and goes, it will even reset itself sometimes without me having to clear the code and CEL. If the faulty sensors remaining in can cause a problem even if flashed properly I need to get them out.

So my question is could this be because the 02 sensors are still physically plugged in ? And if these sensors have been so called flashed out, should I be able to see these sensor values on a ODB reader? if the answer is no then I know the ECU was not flashed properly...

Thanks guys