Added Running Data Below - 0 mph, 27 mph, and 55 mph

Hi all, I have a 2000 RX300 with 200,000 miles on it - which ran ready good to recently.

I had check engine come on with PO1130 so changed O2 sensor Bank 1 Sensor 1 with New Denso near rear of Firewall under car.

That code went away then got PO171 shortly after, cleared and keeps coming back - I have a Innova 3140G Code Reader so can watch all live data and store data too.

Have a bunch of data stored at different RPM"s so can read back and post anytime if that helps

Definitely the rear bank is the issue - it is at STFT B1 -19.5%, LTFT B1 - 52.3%

I read and watched many many Threads and Videos on this code.

So changed Air Filter, Gas Tank Cap, Air Intake Mass Flow Sensor, Oil and Oil filter so so far.

(and O2 sensor Bank 1 Sensor 2 mention earlier)

(See one post that Maybe PCV Valve is the issue - has anyone heard of that causing this PO171 Code)

PO171 still coming up also now get PO300, 301, 303, 305 once in a while too.

Checked inlet connections - Remove Rubber boot on air inlet looked Ok.

Check hoses for cracks or not connected - cannot find anything wrong.

In a lot of Video people do Smoke Test to find air leak so got Smoke Machine and tried it.

Blowing Smoke into the air cleaner with inlet plugged. Do not see and smoke coming out anyplace.

Tried smoke in a small hose off air cleaner - seen smoke out the rear Evap rear of car. Removed plastic cover and it is coming out a open hose pointing down.

Not sure what that hose is - did not look up yet.

Any ideas of what to check next or direction to take ?? I am at a loss right now

If any one wants to see the data I can post it what ever they want to see.

If they think that could lead to direction to take.

Thank you

 

get yourself a can of carb cleaner and spray all vacuum lines and at the base of the intake manifold if RPM'S increase there is the leak. yes a bad pcv valve can throw 171 code replace valve and hose, good luck

 

did you watch this one
https://www.clublexus.com/forums/rx-...l#post10216997

 

Changed the PVC valve - no change - PO171 still comes up

Sprayed Carb Cleaner all over the place - no change in Engine Sound or STFT % while Spraying

Really at a Loss of what next.

 

Watched this Video and Part 2 found Online - For sure rear bank from my data

Not sure it is a Air Leak - when Raise Rpm's the STFT does not change

But when let off Throttle I do see STFT drop then come back to STFT B1 -19.5%, LTFT B1 - 52.3%

So have not figured out what can cause that.

Ideas anyone???

 

https://parts.olathetoyota.com/p0171-code-toyota

 

Thanks for the link - I replaced the O2 Sensor already - possibly New one Bad too???

I have a Innova Scanner and can read all kinds of live data.

If someone know how to Diagnose if it that sensor again would Help a lot.

Thanks

 

the link stated bank one sensor one is the culprit you replaced B1 S2

 

please read this good luck https://www.engine-light-help.com/le...ine-light.html

 

Think I wrote it wrong in the first post - I changed - Bank 1 Sensor 1

This is what it said online where it is - Bank 1 Sensor 1 is actually located between engine and firewall on passenger side about even with back or front pass tire.

That's what I changed out - thanks for finding that

 

OBD made it simple all O2 sensors behind cat are always labeled #2 and bank one is always where cyl # 1 is located. I'm kinda hoping you may have replaced the wrong O2 sensor. The hardest thing for me is remembering where cyl #1 is.

 

From your first post it seems the P0171 codes started after the O2 sensor replace. So I'm wondering if its a bad one.
Maybe you could swap B1S1 and B2S1, I think they are the same.

 

I did some research, check the ground wire on the back of the intake manifold.

 

Ok will check that ground

 

Here is the Running Data at 0 mph, 27 mph and 55 mph

Any ideas anyone??