So i replaced the o2 sensors AND the cats on my gs300 about 4 months and today im getting in my car, it hadnt been off for 5 minutes, i start it up and now my check engine light is on. autozone told me its the P0439 bank 2 code which is the same side i had the problem with before. could my brand new o2 sensors have gone bad that fast? or what else would cause the CEL to come on?

 

nobody knoooows the trouble ive seen. nobody knooooows my sorrow....

 

I would take it in to lexus and have them look at it

 

It could also be that you have a gas leak in your exhaust system

 

Bad wiring?/bad ground?

 

what do you mean by gas leak in my exhaust system?

 

You may have a bad gasket or leak in your exhaust which causes the code. This is the last of the 3 normal things that causes the code to pop up. A heated O2 sensor and a bad cat are the other two. You might be able to find it this way but you will need 2 people. When the car is cold have one person block the end of the exhaust pipe on the side you are having trouble(pass). The other person should look for exhaust gases excaping out of your exhaust system. That would be where you have a leak. Just do it quick before the pipes heat up.

 

If it heats up quick just stuff ur exhaust tips with rags.

 

I just had an exhaust leak fixed two weeks ago. and the o2 sensors aren't even six months old yet. what did u mean by heated o2 sensor?

 

Did you put in the O2 sensors that just plug in or did you have to splice the wires? Pull out the O2 sensor and see if it looks burnt on the end. How does the tip look compared to the one you took out?

 

You need to replace your bank #2 Oxygen sensor. Send a PM to PL Gazi, he can get you a pretty good deal as well. Not that hard installing them too. I believe he has plug and play.

 

i bought the ones that plug in.

 

already replaced all the o2 sensors and the cats

 

OP, did you ever get the issue resolved and what was the cause? I have an 00 GS300 and it had been throwing the same code over the past couple of months, I got the O2 sensors replaced and the code went away for a few weeks before coming back on, any ideas?

 

Wow--The Loin King. Someone's got kids...

I'd check the O2 sensors first...make sure things look a-ok first. Otherwise, slide into Lexus and have the tell you EXACTLY what's going on.