Leines

has misfires 2/4/6, replaced Oil control valve...no misfires now...also replaced rear AF sensor and MAF with OEM denso parts.... Now it failed emissions... CEL came on this am... P0171, P1133 P1153.... these AF sensor codes werent there before replaced MAF and rear Sensor...
from using search p0171 is a MAF code unless followed by other codes.. i have had this 171 before and had toyota clean MAF sensor..code didnt come back.. but when i had misfires toyota said MAF could be issue so i replaced it with everything else.

Ive read that an exhaust leak could also cause these codes, but i wonder how an exhaust leak would make it fail the etest.... i can say it wasnt failed because of CEL lights or leaks.. it missed the emissions test by 0.10

P0171 perm
P0171 pending
P1133 Pending
P1153 Pending

So far all ive done is get a bottle of emissions pass in a bottle, that apparently cleaned the injection system etc.... im running that... filled up with premium gas and hoping that will make it pass but id like to get CEL figured out as well.... 2 months now without my truck...

Leines

Other Work done in recent weeks

Rear AF Sensor
new MAF sensor
Front and Back Oil Control Valves
Fuel injector rebuild o-rings

01rxwhite

Just curious if the code referred to a vacuum leak or an exhaust leak? However, just a suggestion to check something. There is a small hose coming off the MAF sensor area on the back of the air filter canister lid that can sometimes become disconnected when when lifting up the lid to check the filter. I may be wrong on the exact location, but check to make sure it is not disconnected. Could be a simple fix. Also check for other small hose issues around the air intake for possible vacuum leaks.

01rxwhite

Oh, yea... the hose I'm talking about descends or goes down under and behind the air filter cannister. It attaches to a metal tube. Where it goes, I have no idea. Sorry...

GS4_Fiend

iTrader: (22)

P0171 - Bank 1 LEAN

Since you already change the A/F sensor for bank 1. The only thing left would be a vacuum leak somewhere on bank 1 such as the intake manifold gasket, which is on bank 1. You would need to get it smoke tested to confirm for any vacuum leaks. Second, do you have an exhaust leak on bank 1? Bank 1 is the one near the firewall.

Can you type out what the car failed for and what were the FULL emission readings including the C02 and O2.

Leines

I can get the emission test im sure the mechanic still has it.... that hose isnt disconnected rxwhite and from my understand that throw Evap codes i thought?

I guess its possible i have an exhuast leak... but why would it just now throw these codes when they werent there before i reaplaced the rear sensor... it is possible replacing the rear sensor made the computer figure out the front sensors were screwed???

Cheers

GS4_Fiend

iTrader: (22)

No. Both banks are monitor seperately, that's why you got bank 1 and bank 2.

code58

Leines,
I know we had this conversation on another thread but was the REAR sensor that you changed in fact a Denso A/F ratio sensor, part # 234-9009? There was confusion about the difference between A/F ratio sensors and Oxygen sensors (O2 sensor). Because you ordered and got the wrong part once (not sure which part because I don't think you said) I just wanted to make sure you indeed got the A/F ratio sensor that you put in Bank 1. Whenever you get the kind of codes you are showing now (which includes P1133) I cancel 'em out and wait to see what comes up 1st. Assuming you got the correct A/F sensor and installed it, making sure there was no sign of it ever being dropped (they are easily damaged), I would look elsewhere for the reason for the P1133 & P1153 codes.
I don't think the reason you mentioned is valid (see highlight). And indeed an exhaust leak of ANY kind will cause it to fail e-test.
Spend a little time here, a lot of great info if you take the time to mine it. http://www.obd-codes.com/trouble_codes/lexus/ Remember, there's a lot more to this site than this page.

Leines

Yes it was a denso OEM... came in a toyota box... this the sensor that i bought...

http://www.ebay.ca/itm/GENUINE-DENSO...item23142065bd

My question is why did these codes only throw after i got the new rear sensor... since i have a bank 1 and bank2 code... it would seems kinda odd both go bad literally hours after installing the new rear one..

Leines

I should add...i removed the codes.... first thing back is a freeze framed P0171.... and then pending codes for P0171 P1133 P1153..... they are pending codes.... Like stated before i have put in a new MAF also OEM toyota.

code58

Leines,
Let's try and get on the same page here. You say you replaced the REAR A/F RATIO SENSOR. That would be the sensor on the rear of the engine back by the firewall. That is referred to as B1S1. The sensor you have referenced in the link from Amazon Is the WRONG sensor. That sensor is indeed an OXYGEN sensor, NOT an A/F ratio sensor!!! The sensor you referenced in the Amazon link goes under the drivers seat, behind the Cat. Conv. That is the WRONG sensor for the A/F ratio sensor on the firewall side of the engine. That sensor should be Denso part # 234-9009. No wonder you are throwing crazy codes. Step back, take a deep breath and slow down!!! You're spinning your wheels and going NOWHERE!

This is the one you should have

GS4_Fiend

iTrader: (22)

Putting an o2 sensor in bank 1 sensor 1 you will fry that oxygen sensor guaranteed.

Leines

Its because of all this bank 1 bank 2 oxygen a/f and it gets me confused... the part i linked... was indeed installed under the seat behind the cat.. not near the engine... it was suggested to me by the toyota tech as something that could be contributing to my first issue which was a rich code and misfires 2/4/6, and he doubted the oil control valve... since the parts cost so much at the dealer and shipping time from online sources were so long to canada.. i just basically ordered 1 of everything they said could possibly be wrong.. total cost was $280 CAD for the 2 oil control valves, the MAF sensor and the rear oxygen sensor that i linked... all OEM denso parts came in toyota boxes. this was actually the same price as just the one sensor from the dealer. I had my mechanic installed said four parts... and i ended up with new codes as mentioned here...

So i looked into the prices for the A/F sensors you guys are talking about which are installed near the engine.... they are running about $140 for oem including shipping from my source, but i wasnt convinced since they were the pending code... by chance i went out and put my old MAF sensor back in, and removed the neg cable. since the old one wasnt proved faulty, i just reaplaced it cause i figured it couldnt hurt i figured it couldnt hurt anything... the exact opposite happened.... ive drove 200kms and the codes havent returned... not even pending as of now....

would a faulty MAF make me fail the emissions??? seems like the stars are aligning right now...

GS4_Fiend

iTrader: (22)

Bad MAF sensor would cause both banks to go lean.
You stated you change the oxygen sensor behind the cat, thats consider as Sensor 2, which indeed is a normal o2 sensor. Bank 1 Sensor 1 and Bank 2 Sensor 1 is before the cat and it only uses A/F ratio sensor.
Bank 1 is towards the firewall. Bank to is towards the radiator. Make sure you change the right one.

Leines

well all the codes are gone so i think ill just wait on the two A/F sensors unless it still wont pass emissions is is... doesnt look like they were the problem.... is it unheard of to get a defective denso MAF?