My car is throwing the P1153 code (reader actually says P1153 & P1153 P). I checked the front O2 sensor by running an ohmmeter on the two black wires...no continuity. I purchased the Denso 234-9009 part, ohm'd it out before putting it in, and had continuity between the black wires. I cleared the code (and pulled the ECU fuse). After about 15 miles, the CEL came back on again with the P1153 code.

Just for safe measure, I got under the car and ohm'd out the rear O2 sensor, and it has continuity.

Not sure what to do next. Do you guys have any suggestions? Thanks!

 

Just a follow-up to my initial post. I'm still getting the P1153 error code. I read in another post that this code is the P1153: Bank 2 Fuel Control Shifted Lean, which suggests that it is most likely a bad O2 sensor. Just for good measure, I also replaced the downstream sensor (B1S2), but I'm still getting the code.

One thing I didn't mention is that when I replaced the front sensor (B2S1), it was seized really badly and the threads were pretty messed up. I was able to get the new sensor in, but it didn't quite seat all the way down. Might that be giving me trouble?

 

You should use a thread chaser -- or right tap to reformulate the threads. If you have a leak it will give bad results.

Also bank 1 is the firewall side. Bank 2 is the radiator side [just for verification]

Salim

 

OP,
Where did you buy the part from?

 

This is the part I purchased. It's price was much better than any of the others I saw on Amazon. Should I be skeptical? It ohm'd out correctly.

 

I would be skeptical. They selling refurbed and new sensors for very low prices compared to everyone else. The price from Amazon and not a third party seller is $113, and that is less expensive than almost all the other third party sellers under that listing.

 

Thanks for the tips, guys! I ordered the Amazon part for $113, and started the return/refund process for the other part. When I switch them out this week, I'll run a thread chaser into the bung to try and clean it up a little (although there wasn't much thread left).

I'll update once I get the new part installed.

 

Update: I received the new Denso O2 sensor and got it installed yesterday. I ended up pulling the exhaust manifold so I could get it in a vise to chase the threads. It was probably a two hour job to get everything done. I'm happy to report that after 50 miles, everything is working correctly (no CEL)!

Thank you to everyone for your help. The really valuable lesson I learned from this is to not trust third-party sellers on Amazon.

 

Update 2: I’m at 400 miles since my repair and no problems. For anyone interested, here is what I’ve learned…

On my car (1999 Lexus RX300) there are three exhaust sensing O2 sensors that are potential problem sites.

There are two “upstream” sensors, and one “downstream” sensor. The sensors are identified as follows:

· Front sensor, Bank 1, Sensor 1 (upstream…near firewall, rear of engine).

· Front sensor, Bank 2, Sensor 1 (upstream…right behind the radiator, and front-most sensor in the vehicle).

· Rear sensor, Bank 1, Sensor 2 (downstream…the only downstream sensor, right behind catalytic converter).

· “Upstream” or “Downstream” refers to which side of the catalytic converter you are referencing.

When the “Check Engine Light” illuminates, and the code is P1153, it is referring to a problem with the front O2 sensor (Bank 2, Sensor 1).

When the “Check Engine Light” illuminates, and the code is P1133, it is referring to a problem with the rear O2 sensor (Bank 1, Sensor 1).

From what I’ve experienced (and read), replacing the O2 sensor will almost always fix these problems.

What I’ve also learned is that if the price for a new O2 sensor is really good, you should be concerned. Lexmex convinced me that unless your new parts are from Amazon, and not a third-party, you might be getting inferior parts (you get what you pay for). Buy OEM…Denso parts from a reputable dealer.

 

Thanks for sharing. Amazon needs to do a better job of blocking fakes. I don't think they care though

 

I bought a new Toyota/Denso oxygen sensor on eBay, not sure what I was getting. I had emailed Denso to ask how to tell the fakes. They told me some are so accurate that they have to send them to their lab to test them, otherwise there's no way to tell them apart. The stamping on the part looked accurate and the printing on the box looked perfect. I installed it and so far it works perfectly. Time will tell. If it fails early, I'll probably go through RockAuto or somebody like that.

 

I bought on eBay what was purported to be a Denso 234-0009 sensor and installed. ($28) The CEL came back on after about 50 miles. I am returning to ebay for a refund. (I kept old sensor so will be able to use the car. It's our 2'nd car so should be no Problem.)
I reordered another..the picture and box looks authentic. But cost was only $43. https://www.ebay.com/itm/273289772811 I have returned stuff purchased on eBay before and had no problems.
If this one fails, I guess I will shell out the $110+ for a "real" one.

 

The "authentic" box adds $15 to the cost of the crap sensor.

 

For what it is worth I buy almost all my parts from RockAuto and never had a problem.

 

Ok..got the new $42 dollar sensor. The box and the stamping all looked like the real Denso 234-0009. Even had the made in Japan and the bar code on box. (if a counterfeit, it sure does a good job on the appearance.) After installing (I take out battery to make it easier to get to the connector). On first drive of about 4 minutes, CEL came back on. The only code is P0125. (Insufficient coolant temp for Closed Loop Fuel Control for a predetermined period of time.)

I rechecked all the adjacent hoses etc to try and make sure i did not pull something loose during installation. Everything looked ok to this novice. After reset, test drove again, with same results...P0125 code.

Question for all the experts on this forum...although only code P0125, in your opinion, is the oxygen sensor the culprit?