Hi all,

Been part of these forums for a long time but in the GS section. So, I have major issues with my 2001 RX300.

About 3 mos ago I got a PO1135 and PO1155 CEL. I believe these are rich codes and have been getting pretty poor gas mileage, drivability was unaffected. I decided to replace my bank 2 sensor 1 air fuel ratio sensor (front of engine near radiator) with a Denso part 234-9009. Install took about 5 min; i do car work on my own most of the time. I did not reset the ECU, only reset CEL with my scan tool. Started up and sounded fine.

Later that day I took it for a drive. Not more than 2 miles up the road I get a flashing CEL and truck goes into limp mode. I drive less than 1 mile more to see if I can make it home and suddenly heard a pop and then hissing noise, decide to just pull over. I look under the truck and all exhaust components directly under engine are glowing red hot! Needless to say I got it towed to my mechanic which isnt open until Tuesday.

What could've caused this? Could it be that the person on EBay sold me the wrong or bad sensor? Could a wrong or bad sensor do this? I'm really upset because I think I could've fried my cats and who knows what other damage occurred. I did notice when replacing the sensor that the new one's wire was a bit shorter (by maybe 2") than the one that came out of the b2s1 location. I thought nothing of it as perhaps the previous owner put an aftermarket sensor in there once before.

Please or let me know your thoughts on this. I did a lot of research but never heard of this exact thing happening revolving around these codes and air fuel ratio sensor replacement.

Thanks,
Nick

 

knock sensor failure? Long time ago, I got air ratio sensor failure. After I replaced it, I got knock sensor failure.

 

What are the new codes?

 

Unfortunately. I didn't have my scantool with me when the tow truck brought it to the mechanic. If I had to guess, based on how it was idling felt like codes for st least random/multiple misfires.

 

Long story short. The person I bought the sensor from sold me either a bad part or made for a different vehicle and made my truck have issues. Luckily, I didn't melt my cats. But, it did need (2) air fuel ratio sensors, bank 1 and bank 2. Sadly, my shop never told me that it just needed 2 new sensors and just went upon themselves to buy them from Lexus at a premium without me knowing. Wound up being $270 each sensor plus labor. A $780 bill. If the jerk that sold me the wrong sensor would've sold me the right one the worst that would've happened is the CEL would have just stayed on with a rich code telling me that I need to replace the other one as well, and at a bargain price. This fix should've cost me no more than $200 and 30 min of my time.

What a waste of money. At least it's fixed and I pick it up tomorrow.

 

trying to understand one thing. How did O2 cause exhaust glow bright white?
exhaust components directly under engine are glowing red hot!

Wouldn't it rather be clogged cat?

 

Here is one scenario:
Computer gets corrupted signal that the system is running lean from the O2 sensor. It starts pumping more fuel into the intake. The system runs rich and lets out unburned fuel [not enough real oxygen through the intake]. Cats start working overtime to neutralize the unburnt fuel before letting it exit through the exhaust.

Salim

 

You're right Salim.

thanks all