Shawn71

Hi everyone,

Wondering if someone can help me out with this--my Check Engine light came on in my '03 ES300. I had Auto Zone hook up their electronic reader--it comes up with the code P0031. According to the code list, this means that the sensor control heater is low. I'm almost certain they're referring to an oxygen sensor. This sensor is located in Bank 1, Sensor 1. Does anyone know where that one is? There are 4 oxygen sensors on my Lexus, I believe. The only one I can see is on the exhaust manifold at the front of the motor, as I'm looking at the motor from the front of the car.

Any help would be greatly appreciated. Thank you!

--Shawn

yeldogt

Just make sure you have the correct code and that you cross reference it - don't trust Auto Zone -- the cross reference they use can be incorrect.

Find the codes for your specific car - Just to be sure.

That said - Sensor 1 is the pre catalytic sensor -- the one on top by the exhaust manifold

I believe bank 1 CYL 123 (not firing order) is the bank by the radiator -- so it should be the one visible when you open the hood.


I would make sure that no fuses for the sensor heaters are blown and also that the connector for the sensor is clean and tight -- but most likely the heater in the sensor failed. Toyota uses a more complicated sensor than most - its not just an O2 so get the correct sensor.


If you had a code reader you could unplug the sensor and reread the codes you would then get an open sensor code on the same bank -- you would not have to do any more searching for the correct bank. Having an inexpensive code reader is a great addition to the tool box. The O2 sensor is very easy to replace -- just buy a cheap O2 socket and you will have it out in no time -- the new sensor will have some anti seize for the threads and the connector will just plug in. Good Luck

MikeLex

This is not correct. Bank 1 Sensor 1 is the one near the firewall.

yeldogt

YES -- MIKE IS CORRECT!


I just replaced the number #5 coil and was not thinking correctly.

Firewall is 1 - 3 - 5

Its a little more difficult -- do a search someone just did it -- just take your time and get the correct sensor.

Shawn71

Thank you for the responses--I appreciate it!

mildawg

sooo my car started acting weird today, when its below 1000rpm's it acts like a car with standard manual gear box which is on very low revs(as if its missing serious power) for its gear... when it hits 1000-1500 rpms, it starts shaking not too violent but there is a shake none the less ...
(car does that on park gear as well)
any tips before i get it check out this thursday??