briangloe

Replaced front and back sensor twice and got same reading for bad sensor. Second time rewired directly without the harness. Car runs fine, however, have check engine light with same faulty sensor message. Any ideas.

Have a'97 LX450, high mileage, runs great.

mitsuguy

iTrader: (2)

are you sure it's an o2 sensor error?

whats the EXACT code?

briangloe

Don't have the specific code number any more. The Lexus dealership in Atlanta read it, as well as my local mechanic, and the folks at advanced auto parts read the same error, problem with my oxy sensor. That's why I replaced it, them, cleared the computer and the reading came back.

My local mechanic said that it was a problem that happened because it was an after market, advanced auto o2 sensor, instead of from Lexus. And that this was known to happen.

mitsuguy

iTrader: (2)

well, that is quite possible - aftermarket o2 sensors are rarely as accurate and as good as the stock stuff (however, stock is also available in the aftermarket as well)

there are other things that can cause o2 sensor errors, which is why I asked for the specific code, as I can look up specific other issues that may produce your code that may not mean the o2 sensor is bad, but that some other part of the system is affecting it...

was the sensor actually tested it before it was replaced?

we get this all the time, specifically with EGR valves - lots of things flag an EGR valve, but rarely do they fail...

if you can get the code pulled, let me know...

briangloe

I'll get the code, either that or your can tell me an easy way, no black tape, to disable the check engine light.
Thanks

Lexmex

This very true on aftermarket sensors with regard to RX300s we have had in the forum. There have been a few who have gone an aftermarket sensors like Bosch, Walker and had issues, but put in a Denso and things are back to normal.

mitsuguy

iTrader: (2)

no way to really disable it... you can have it turned off, but it will always come back...

briangloe

The computer codes are PO135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) PO141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Is it just a matter of the wiring being wrong. I was under the impression that if that was the case the sensors would work at all and the car would not run.

Really appreciate the help.

mitsuguy

iTrader: (2)

o2 sensors are not critical sensors to the vehicles operation (about the only sensors you absolutely HAVE to have are crank/cam sensors) most other sensors, like the o2's, can be lived without, the car may just not run right...

It almost sounds to me like something in the circuit is messing things up, not necessarily the o2 sensor, however, it still could be the new sensor not working properly... I don't have access to it this morning, as someone turned my computer off at work, so I can't access my troubleshooting data... I might run by later once I put the dash back in my car so I can look it up though...

mitsuguy

iTrader: (2)

here's troubleshooting procedure:

briangloe

Really appreciate the help and info. You're the first person with this clear of an idea of what to do next. Kind of surprised the Lexus mechanic in Atlanta or KC didn't come up with this.

I'll let you know how this works out. Thanks again.

mitsuguy

iTrader: (2)

any time man...

it's just a matter of using resources...

and although a little off-topic, but dealer mechanics sometimes try to solve problems by throwing parts at it, whereas a good independent shop does the right diag work the first time, as we don't just have parts laying around for every car we work on

example: p0135/141 comes up, dealer solution - replace o2 sensor; our solution - test o2 sensor first before condemning it...

taanderson

I have a 2000 GS 300 with the P0141 code.

The dealer is recommending that I replace my O2 Sensor as well.

Do you have any troubleshooting procedures for the P0141 code?

Thanks in Advance!

mitsuguy

iTrader: (2)

First off, welcome to the forums...

Secondly, your troubleshooting instructions are pretty much the same as above - here's wire colors and such:

taanderson

Thanks for the quick reply! I figured it would be a similar procedure but I though I should ask anyway.