Low brake oil...... I am willing to buy this argument........ It has only happened in the cold temperatures so far...... so the expansion and shrinking of brake oil is a possibility.

If it were the o2 sensor, shouldn't the check engine light come on ????? Which o2 sensor are U thinking?


Let me go check the brake oil while U reply

 

Yep the "Check Engine" light (symbol of an engine) would come on if the computer sensed a problem with the oxygen sensor and there would also be a diagnostic trouble code(DTC) stored so the dealer would have found that during their inspection. They may not have noticed if the brake fluid is slightly down. It has been my experience that the warning light will come on long before the brake fluid level reaches the low mark. As brake pads wear normally, the caliper piston has to move out of the bore to compensate. This means that the brake fluid level will drop.

 

Brake fluid level was fine.........Any other ideas

 

In my case, the light has come on after driving awhile and the car was warmed up. I will check the brake fluid anyway though.

 

Even the lexus dealership is clueless............since your car is also warranty, can you take it to the dealer and lets see if there is a better mechanic there, maybe a smarter one.

 

its most likely the brake pedal switch...do a search, it's been posted about before:

https://www.clublexus.com/forums/rx3...driving-2.html

 

This looks like the likely cause... Thanks GQD