I have 2002 SC430 with 90K mile.

I brought it to one Autozone and they said it's coolant problem.
-> added coolant

I brought it to a Lexus dealer and they said b1s1 oxygen sensor needs to be replaced.
-> didn't believe

I brought it to a Meineke and they said thermostat needs to be replaced.
-> did, but the engine check sign came back on after 5 min driving.

I bought a OBD II reader and found the error code is P0125, and erased it. But it came back on after 5 min driving.

I bought b1s1 O2 sensor (BOSCH 13441) and had a local repair shop replace it.
-> drove 120 miles and deleted VSC & VSC off signs by zero calibration, but the engine check sign came back on

I brought it to an Advanced Auto Parts and they said the error code is P0125 and deleted it.
-> It came back on after 5 min driving.

I checked the temperature gauge before and after driving, but it seems normal.
Now what should I do?
Many thanks in advance.

 

P0125 error covers the following components: Have you cleaned your throttle body lately? Possible a too lean mixture. If the vehicle is short of fuel, the air-fuel ratio is LEAN and the P0125 will be recorded and MIL then come on.

Also check the PCV hose for looseness, or cracks or disconnections. We had a few of those issues lately. Also take a good hard look at your gas tank cap. Check the gasket damage or deformation. The fuel and emissions systems are pressurized if there's a leak it will throw a code.

 

I have the same issue and code..P0125. I had P0135 and changed by b1s1 o2 sensor at the Toyota Dealership. I think they screwed something up, because the P0135 went away but now I have a P0125. From everything I've read, it's still the 02 sensor....either wiring or the sensor itself. I'm not sure if the toyota dealership did as good as a job as they should have.

Will probably go to the lexus dealer and see if they can fix this wrong.

Did you ever fix yours?

 

Have you fixed yours? Cost?

 

I have 90k, I solved the problem by replacing the PCV valve.
symptom, like a mis when initial acceleration. Hope this help

 

Take a look at this article https://www.autocodes.com/p0125_lexus.html

Based on what it says, I think it is your temperature sensor. Does you temperature gauge on your dashboard work?

A P0125 and a P0135 are two different things. Is it possible you have both codes stored in your car?

Do you still have the reader you bought? Can you go check for codes and tell us which ones are present?

 

Disregard my previous post. It turns out the P0125 could mean different things on different cars. Take a look at this Code list from Club Lexus
https://www.clublexus.com/forums/att...-dtc-chart.pdf

Since the dealer says it is the O2 sensor, I would go with them. I know a Denso sensor is about the same price or cheaper than a bosch sensor and the Denso is the Origional Equipment Maker. You may have to replace the bosch with the OEM. If you used the universal bosch with spliced in harness, than I would REALLY recommend you go with the Denso.

 

Did you ever get this issue resolved? What was the culprit?

 

Thank you! I am having a trouble with this code too on my '04 sensor so thank you!

 

Thomas, why don't you start a new thread and tell us what your situation is (Or you can just add on to the post)

O2 sensor probs are always tough because the sensors aren't cheap and you want to try all kinds of ways to get around the problem. Usually the solution does end up being changing the sensor. Still if you had recent exhaust work done, or your car is louder than it used to be, it might be something else. So feel free to let us know what your story is.