A year or so ago I had my primary O2 sensor replaced under warranty by the Dealer. The O2 sensor had gone faulty and there was a TSB which listed some '05-'06 TCs as the victims.

Anyhow, the factory replacement at my dealership was a Denso 4-wire O2 sensor.. and for those of you who may want to replace your primary O2 sensor, here's some info:

Manufacturer: Denso
Part Number: 234-9044
Wires: 4
Direct Fit: Yes

Also fits the following vehicles:

2007-2007 Lexus ES350
2007-2007 Lexus RX350
2005-2007 Scion tC
2005-2006 Scion xA
2005-2007 Scion xB
2001-2005 Toyota 4Runner
2001-2007 Toyota Avalon
2001-2007 Toyota Camry
2001-2005 Toyota Celica
2001-2005 Toyota Corolla
2001-2005 Toyota Echo
2001-2005 Toyota Highlander
2001-2005 Toyota Land Cruiser
2001-2005 Toyota MR2 Spyder
2005-2005 Toyota Matrix
2001-2005 Toyota Prius
2001-2007 Toyota RAV4
2001-2005 Toyota Sequoia
2001-2005 Toyota Sienna
2001-2005 Toyota Solara
2001-2005 Toyota Tacoma
2001-2005 Toyota Tundra


Best prices? http://frugalmechanic.com/auto-part/...-oxygen-sensor

 

good to know. thanks.

 

what's even better to know is, thier is no primary o2 sensor. thiers only one period. ~ a/f sensor~

 

Not sure what you mean... we have two O2 sensors. A primary O2 sensor, a 2nd O2 sensor which is on the S-pipe.. and some people like me have a 3rd wideband.

 

Our setup isn't like most setups.... we have a wideband as our primary oxygen sensor where as most vehicles have a regular HO2S. Widebands are more accurate yet more expensive... maybe thats what he means... and yes we have a post 02 sensor which basically just monitors the performance of the Cat...

 

Yes our primary is a 4-wire as I have stated before. And yes it is sometimes called an A/F sensor.. but it is NOT a wideband. Widebands have 5 wires always.

It's no different than most primary 4-wire O2 sensor. This is our factory replacement because it comes at the correct wire length and correct plug.

 

quick question...

using a scan tool hooked up to OBD-II port, i have monitored AFR's as low as 12.05 and as high as 18.07 from the primary stock O2 sensor.

is it safe to do some tuning using the primary O2 sensor's readings?

i'm guessing it's OK, but just wanted to make sure.

 

The sensor on the header is an A/F sensor, I figured this out when I destroyed my original one when I was installing my DC header.

 

A Wideband (5-wire sensor) is recommended to tune off of.

 

is there any reason why? any difference besides possibly reading a wider range?

if i'm tuning NA and aiming for a 13:1 AFR, then shouldn't the readings from the stock primary O2 sensor be sufficient?

just trying to learn more and would appreciate it if anyone can drop some knowledge on me.

 

it is different as it doesn't cycle like most other HO2S sensors do (75mv to 850mv, give or take). It stays around relatively the same voltage and doesn't vary too much. I have a few screen shots of the pdf stating this information. Also, I could have sworn that I have read our primary HO2S sensor was a wideband (hybrid wideband) , but it is different from most widebands as most they usually vary from 0-5V and ours stays around 3 I believe (I believe I have heard this information from dezod.... anyone??).

 

^ from my scan tool, when it recorded AFR's in the 12's to the 18's it showed the voltage rating varying from 2.xxx to 4.997.


FYI, i'm hooking up through OBD-II port using Auterra Dyno-Scan tool through my laptop. screen shots of my findings if anyone is interested.