Do I have the correct Delphi upstream sensor for my 04 Corolla?

[Jimigunne]

It's a Corolla sedan, std 1.8 L engine. I have 184K miles on it, and the gas mileage has gone from around 38 mpg HWY when I first got it (at 90K) down to 31 mpg HWY. This is very bad news, when I put 550 miles a week on the car! Some of this decrease may be due to the switch to "up to 10%" ethanol blend. Well, I thought I would try installing a new O2 sensor, the upstream one, as I have already replaced the downstream one (didn't seem to affect gas mileage). For about $55.00 I got a new Delphi sensor from Rockauto. The p/n is: ES20157. The first thing I noticed is that the connecting cable is too short, and also the connector is wrong (it was advertized as "OEM"). The new sensor has a roundish connector with four female contacts for the engine-side pins. But the correct connector to mate to the engine is rectangular, and has four flat bade-type contacts. I really didn't know what sensor to choose, they had many different upstream sensors, ranging from 35.00 up to around $100, and so I just chose one in my price range, figuring the cheapest ones are probably poor quality.
I don't have much faith in some rep with Rockauto being able to tell me "yea, that is the wrong one, you need x---- sensor", so I thought I would see if some motorhead here has the info on compatible sensors. Thanks!

[invader]

Does the connector not look like this?
http://www.ebay.com/itm/Delphi-ES201...item1c1d450bd8

Are you sure you're trying to replace the upstream sensor on exhaust manifold behind the engine?

DENSO Part # 2344800 like your OEM would be a good choice, although your Delphi should be fine.

http://www.rockauto.com/catalog/x,ca...2B1.8L%2BL4%2B

Amazon

Amazon

[invader]

Are you sure your Corolla is not a 2005+ DBW with upsteam air/fuel ratio sensor which have a rectangular connector, instead of an upstream O2 sensor?

http://www.rockauto.com/catalog/x,ca...A%2BCOROLLA%2B

The 2005+ Corolla uses the same downstream O2 sensor with rectangular connector as on 2004 and previous Corolla models. That would explain why you were able to replace your downstream O2 sensor while you thought your Corolla is a 2004, when it is in fact a 2005.

[MasterTecInSTL]

I think invader may be on to something. Look at the tenth digit of your VIN number. It will tell you the year of the car. If it is "4" then you have a 2004. If it is "5" then you have a 2005. Even if the car was made in 2004 it could still be a 2005 model which is why the VIN number is more important than the door jamb sticker.

If you have an '04 the Toyota number is 89465-13030 and is a "traditional" oxygen sensor.

If you have an '05 the Toyota number is 89467-12010 and is an "air/fuel" ratio sensor - and considerably more expensive.