code58

Leines, this is making my head hurt. I'm not at all convinced that you even understand what you replaced or what the parts are called.


This is what you said you replaced. It clearly says AF sensor. I don't see any mention of the Oxygen sensor that you said you replaced under the drivers seat and that you link me to as the A/F ratio sensor that you bought.

Did you in fact replace the rear A/F ratio sensor B1S1 back by the firewall as well as B1S2 (Oxy. sensor) under the drivers seat ?, since on your list of parts replaced you have the A/F sensor, but NO Oxy. sensor. ????
Since the Oxy. sensor (under seat) rarely ever go bad, I question your mechanics knowledge as well as the fact that what he said would fix it, didn't.

code58

Unless it's been dropped, it's highly unlikely.

thomas1

Good morning Roger, you are such a patient and helpful man...Good Troubleshooting skills on this one...I think you have it dialed in.

code58

Did I mention that "dialing" makes my head hurt, this kind anyway, if ya know what I mean.

BTW, when are you visiting family (daughter?) in So Cal. again?

Leines

Ok let me try to explain this again.. please diseregard the messages before as you keep going back to them... i was confused as people call both O2 sensor and AF sensors and they are sold in packages together for our unit 2 for the front and 1 for the back... yet back is oxygen and front is A/F.... i understand it now but i was confused for this reason before...

The TOYOTA DEALERSHIP were the people who told me replacing the rear oxygen sensor was a step to fix my first issue... which was again the P0172 rich followed by 2/4/6 misfires... the TOYOTA DEALERSHIP said there were three things they would replace and in order they were
1) mass air flow sensor
2) Rear O2 sensor ( referred formally as a AF sensor)
3) oil control valve..

Since the prices from dealer was very high $300 each part almost.. i bought all four of them TOGETHER for $280.. and at my instruction had the mechanic install all four of them for a reduced labour rate....

Once he installed them.. the truck was taken to emissions ( CEL off) and it failed emissions.. about 40km later the light came on... P0171 perm followed by P1133 and P1153... which is when i came here to find out these codes.... the reason i was asking about the rear effecting the front was because these codes were not present before.... and reading online they only point to MAF or AF sensors... believing i just replaced the MAF with denso OEM i figured the front sensors were bad.... however like i stated in my previous post... I decided myself to go back and replace my the new MAF with my old MAF just to rule out the possibility of the MAF yet again...

To my surprise the P0171 and other codes have no returned...

So i have concluded that my original P0172, P0300, P0302,P0304,P0306 was fixed with a Oil Control Valve.
And this current P0171 issue was caused by a faulty new Denso MAF...

I thought my last post was clear enough.. hopefully this one makes it a bit clearer that im not an idiot.. i do have some idea what you are talking about.. I was just mistaken when i was sold a rear oxygen sensor by a seller who was referring to it as a AF sensor, even tho it was clearly the correct part toyota suggested to replace...and the one which was removed was rusted and seemed to have something rattling around inside it....

diverchris

Not sure if your issues have been resolved; if you purchased all your sensors from Toyota/Lexus dealership they come with a 12 month/ 30000km over the counter warranty. Dealerships do not like to replace sensors so it is an uphill battle; but I've done it

Leines

Thanks, I purchased them through a third party seller but he has already agreed to take back the sensor without the oem box and just send me a paypal for the return price.... im going for a retest on the emission tomorrow..ive drove 300km now without a CEL back and the truck is running like a top once again... so im hoping easy pass on emissions now...

Cheers

code58

Thanks for the clarification Leines. My head hurts a little less now I would really be surprised if the Denso MAF left Denso's factory bad. The MAF is a delicate sensor and if you've ever seen delivery people handle the boxes, you wonder how ANYTHING ever arrives in one piece. And this means at all levels of the delivery chain, from leaving the factory on.
I truly hope it passes smog and your problems are over!

Leines

Well back from the emission centre with good news... it passed with flying colours... it wasnt even close...

the reason it failed last time was the oc% the limit was .70

First reading at 2500 RPM was .79 and at idle was .82
This test at 2500RPM is .24 and at idle was .23

Big Difference....

Thanks for all the help yet again Club Lexus.... Code58 as well as the others throughout my threads..

Cheers

Should add my fuel milage is 13.5L per 100km or about 17.4 mpg on reg octane

code58

Success is ALWAYS good news!