Hi guys, my mother has a 1999 RX300 with 100k miles and is giving the CODE P1155.

Tires plus said they can fix for $250 and local shop said $550.

Just wondering what is causing this code to come up?

where is the part located and can I maybe clean it or replace myself to save my mommy some $$$$.

Thanks!

 

A quick search will reveal that it's the A/F Ratio Sensor Circuit Malfunction on Bank 1 Sensor 1.

 

I did search and was little confused.

where is the A/F Ratio Sensor Circuit located exactly?? under the car or under the hood??

 

Bank 1 sensor 1 is discussed here
https://www.clublexus.com/forums/rx-...el-sensor.html

At 100K it might be the sensor that needs replacement OR it can be due to other things. Lexus for sure and other shops can narrow it down to root cause.

If it is the sensor, then there is a possibility that while taking it out, the manifold gets messed up. Based on the posts I have seen, the low cost guys tell the customer up front that there is a risk. Places that charge more, have the fat built in. So check with them

I had another code but, that was also pointing out to Bank1 sensor1.

Salim