Code P1003 Bank 1 Sensor 1 (O2 sensor). I would like to replace this sensor myself, I am not sure where it is located. Also in looking on-line for O2 sensor replacement, they only speak of upstream and downstream. Any help would be appreciated. I have a 2008 RX350 3.5.

 

That should be upstream prior to the cat converter..If I am not mistaken there is a left and right one and one of them should be bank 1 sensor 1. Let me see if I can come up with a diagram...

 

Couldn't find a diagram but found this info...

"Bank one, sensor one is the sensor on the firewall side of the engine, the first sensor in the exhaust stream."

Not sure if its 100% accurate, maybe someone else can confirm...

 

Thanks, Bwsteg

 

yes you just look up as mentioned above and you should see it

 

It is 100% the one above the cataytic coverter closest to the firewall. It's a little difficult to het to.

 

If being asked left or right....it would be considered on the rightfor installation purposes when actually it is in the rear of the engine.

 

Thanks to all that responded. I will now try and tackle this job myself. Wish me luck