P2241 Code Causing CEL

[SAC-CA-Runner]

OK. So a little back story, engine blew up so had to put a new V8 engine in. I replaced the headers with Doug Thorley's and some high flow cats. I also put in two brand new Denso front O2 sensors. But for some reason I keep getting the P2241 code. I clear it, then next time I start my 4R it comes on after a couple of minutes. Can this be because of the 02 spacers I have in downstream and lack of rear cats? The exhaust shop did a URD type Y-pipe in 2.5in going into a dual 2.5" to single 3" Y. And yes...I know, I'm in CA. I don't care cuz I'm moving next year and the govt here can bite me. So don't lecture me on what I have on my car and the fact it's not CARB compliant. Anyway, being the 02 sensors are new can it be something else? I cleaned the MAF just to see. Didn't help. Do I need the URD plug in instead of running 02 spacers in the rear? Does anyone have an app they like to use that can read 02 voltages. I'm using Torque and it seems to not read the 02 voltages correctly. I don't mind paying if need be. My plug in thing is a BT that plugs in the OBD if that is the issue. May not be able to send the info quick enough? Thoughts? Could a brand new 02 be bad?

 

[Jrsme93]

I also am plagued with the P2241 on my 4th gen, mine is a V6 however. The code is for an air/fuel ratio sensor which are pre-cat. While looking online at sensors I noticed there are two different sensors branded Denso however, one is not made by Denso, the part numbers are indeed different and the price difference is huge. Did you by chance purchase these cheaper "Denso" sensors? Toyota's are very picky and will not recognize many aftermarket sensors, thus tripping the code again. If you're not getting the catalytic converter codes the rear spacers are not your issue.

 

[SAC-CA-Runner]

I also am plagued with the P2241 on my 4th gen, mine is a V6 however. The code is for an air/fuel ratio sensor which are pre-cat. While looking online at sensors I noticed there are two different sensors branded Denso however, one is not made by Denso, the part numbers are indeed different and the price difference is huge. Did you by chance purchase these cheaper "Denso" sensors? Toyota's are very picky and will not recognize many aftermarket sensors, thus tripping the code again. If you're not getting the catalytic converter codes the rear spacers are not your issue.

Interesting. Didn't know there were "cheapo" Denso sensors out there. I bought mine from ebay for like $70 but per the ad they say they are OEM and the packaging sure looked OEM. My drivers side is working fine. Only reason I replaced both my front 02's is because my original drivers side would NOT come out without damaging it so I figured just replace both. I may put my old passenger one back in that was working to see if the code goes away and then I'll know it's the sensor and not some wiring issue up/downstream from the sensor. And if that's the case...I'll probably get lazy and leave the old one in. HAHA

 

[DoctorDemento]

You could also swap the front sensors side to side and see if the problem follows the sensor (getting code for other side) or stays the same.

 

[SAC-CA-Runner]

You could also swap the front sensors side to side and see if the problem follows the sensor (getting code for other side) or stays the same.

Oh shit...why didn't I think of that?!? That's what I used to do when I worked on the old Audi 2.7T's. Not sure why I didn't think to do that here. These connectors are such a pain to get to tho. Ugh. I ordered another 02 from Amazon, instead of the one from Ebay along with an 02 wrench that will make it easier to do than with the socket and wrench.

 

[General Kornilov]

Out of curiosity, what killed your previous engine? Yours is literally the first V8 casualty I've come across since I started looking into 4.7L 4Runners.

 

[SAC-CA-Runner]

Out of curiosity, what killed your previous engine? Yours is literally the first V8 casualty I've come across since I started looking into 4.7L 4Runners.

Some dipshit previous owner put stop leak in it. Then I believe it clogged the radiator. However, when it backed up it didn't blow one of the large radiator hoses causing enormous amounts of steam to come out. No, it blew the small hose going to the overflow tank and when driving at highway speed I never even knew that coolant was coming out. The temp sensor never budged as many techs have told me that the steam alone can keep it within temp. Odd, but OK. But with no coolant, we all know what happens. Well, bank 2 got so hot it melted my knock sensor and the intake manifold. Lesson learned, pull over AS SOON as CEL light comes on and don't assume it's just some minor hose or sensor going bonkers. The CEL was for low coolant, but figured it was something else since the engine temp never budged (see steam reasoning above). These motors are bulletproof so don't let my misfortune sway you. I haven't taken the blown engine apart yet to see how bad it really is but when I do I'll be taking lots of pics to share. Pics are the melted sensor and some of the coolant that came out of the radiator. Bigger chunks came out when I flushed it. Good news is...now have a 112k motor with all new timing belt, water pump, AC Comp (was going out), headers, 02's, seals, spark plugs, radiator, hoses, bigger trans cooler, etc. She's ready to go for at least 300k. Need to flush the tranny tho just in case said "dipshit" above didn't use some crap fluid.

 

[General Kornilov]

Thats sucks.

Luckily, it seems like you've recovered well from that ordeal.

 

[SAC-CA-Runner]

Thats sucks.

Luckily, it seems like you've recovered well from that ordeal.

Well...minus the checkbook. That may take a little time. :-(

 

[SAC-CA-Runner]

Well...update! Swapped out the Bank 2 Sensor 1 with a Denso 02 Sensor off Amazon and sure enough code went away!!!! Yay! So I was going back and forth on replacing the driver one as well since it is also a Fleabay 02 Sensor. This morning I'm driving and my car smells really rich. So I say F it and buy Torque Pro to run even more diagnostics. Pull the codes and what do I see? P0171 - Powertrain System too Lean (Bank 1) and P2195 - Powertrain 02 Sensor Signal Stuck Lean Bank 1 Sensor 1. F**kin A! Soooo, ordering another Amazon and requesting a refund on these. I will update on Sat once I get the other one in. In the meantime I'm going to attach some pictures and info so others that search won't get fooled.

Ebay Denso Sensor for 4th Gen 4Runner 234-9051 (do not use!)

As you can see, smaller box is Made in the USA (Amazon) and the other is Made in Thailand? But the box says Made in Japan! Which is it?!?! Also ON the sensor it is etched in "Assembled in USA" and the other just says "Japan". Plugs look somewhat identical except fort the blue tape. Also, USA box is smaller and opens at the end. The USA sensor also comes with a very small packet of copper color anti-seize. I hope my trying to save a couple of bucks helps other people in the future.

 

[earthrealm]

Well...update! Swapped out the Bank 2 Sensor 1 with a Denso 02 Sensor off Amazon and sure enough code went away!!!! Yay! So I was going back and forth on replacing the driver one as well since it is also a Fleabay 02 Sensor. This morning I'm driving and my car smells really rich. So I say F it and buy Torque Pro to run even more diagnostics. Pull the codes and what do I see? P0171 - Powertrain System too Lean (Bank 1) and P2195 - Powertrain 02 Sensor Signal Stuck Lean Bank 1 Sensor 1. F**kin A! Soooo, ordering another Amazon and requesting a refund on these. I will update on Sat once I get the other one in. In the meantime I'm going to attach some pictures and info so others that search won't get fooled.

Ebay Denso Sensor for 4th Gen 4Runner 234-9051 (do not use!)

As you can see, smaller box is Made in the USA (Amazon) and the other is Made in Thailand? But the box says Made in Japan! Which is it?!?! Also ON the sensor it is etched in "Assembled in USA" and the other just says "Japan". Plugs look somewhat identical except fort the blue tape. Also, USA box is smaller and opens at the end. The USA sensor also comes with a very small packet of copper color anti-seize. I hope my trying to save a couple of bucks helps other people in the future.

SO just to be sure, you were also getting p2241 code?