Sensor Problems W/ 99 Rx300

[ahh-lee]

I have an 99 RX300. My engine light came on and I did a scanning. The following codes came up; p1346, p1351, p171, p136. I've changed the Bank 1 Sensor O2, code p171 disappeared but came back the following day. How do I go about fixing these problems? Any diagrams are extrememly helpful aswell.

Thanks, Ally

[code58]

I have an 99 RX300. My engine light came on and I did a scanning. The following codes came up; p1346, p1351, p171, p136. I've changed the Bank 1 Sensor O2, code p171 disappeared but came back the following day. How do I go about fixing these problems? Any diagrams are extrememly helpful aswell.

Thanks, Ally

Ally- exactly what sensor did you replace? Whenever you get a flurry of DTC's like that, it is safe to assume they can't all be legitimate, it's brain is scrambled. You have to delete the codes and see what comes up FIRST and address that diagnostically. If you have a scanner (everyone who owns a car that is out of warrantee these days should own one), cancel the codes and see what comes up. For kicks, cancel 'em again and see if the same thing comes up again. This should help you address the P0171 http://www.obd-codes.com/p0137 This should also help http://www.obd-codes.com/trouble_codes/lexus/

I am assuming you realize that Bank 1, sensor 1 is firewall side of the engine and Bank 2, sensor 1 is radiator side of the engine. Bank 1, sensor 2 is behind the catalytic convertor under the drivers seat. You may have known this, but better safe than sorry.

[Bmyers]

I had P171 on my 2000 RX300 and it was resolved by replacing the MAF sensor. I tried cleaning it a few times but the code would always come back after a week or so. Finally, a month or so ago I spent the $100 to replace the MAF (which takes about 30 seconds to install) and the code hasn't been back since.