p0172 p0175 CFL

My truck has been running a little sluggish for a bit but I've been working on routine maintenance so I didn't want to go chasing Gremlins till I was satisfied that everything is how it should be. Well the old girl decided to throw gang signs at me, p0172 p0175. I'm thinking this might be those 02 sensors. Any body have these codes?




Oh and just for giggles, the damn truck is running a lot stronger right now after the CFL gang signs

 

Could be both O2's are dying at the same time but usually unlikely. I would look towards things that can case both banks to go rich. A dirty maf, vacuum leak post maf.

 

Have you been adding additives in your oil or gas? IIRC you mentioned you have. Might be those additives in over abundance causing both banks to trip simultaneously.

 

I replaced the MAF, air filter and cleaned up in there about a year ago, I may go back in there and take a look around. I usually do the fuel system cleaner after oil change but I haven't done it yet.
Only thing new recently is oil change about 2 weeks ago. I have a few things on my 100k maintenance list, 1 is all 4 02 sensors. I cleared the code this morning and I will see if it comes back on. Funny thing is my truck is running better

 

2019 Tundra Flexfuel

I have the same codes, and I noticed they came up after I used an oiled filter (cold intake). The MAF was damaged by it so I replaced with a new one, not realizing yet that it was the oil of the filter, cleared the codes...now its back. I bought a dry cold intake filter and its on its way...but in the meantime, what do you guys suggest I do? should I spray carb/choke cleaner in the throttle body (post MAF) and see if it cleans up any other possible fowled sensors? The truck doesnt have a MAP...so im assuming the next sensors are the O2 sensors. Anyone can give me some insight on this Id really appreciate it

Thanks...your brother in Tundra

 

If the O2 sensor fails, it will run rich. Mine felt rather spry when the O2 sensor went out as it was putting too much fuel in the system as default without O2 sensor reading to help the computer correct it. Also stunk like unburnt fuel from the exhaust. That rich condition will eventually cause the cats to fail. Fix ASAP.

 

I need to replace my downstream 02 sensors myself. I took a look at one of them that was causing the check engine light to trip and it was completely coated in black soot.

 

Reviving this old thread...
So I've got these same codes and the last time I got the p0172, was after Merus. The filter was super dusty, so I knocked it out real good and cleaned the MAF. The code went away. So I did T2S and changed the filter omw back, somewhere in NM. A week later I got p0172 and p0175. So I guess I'll try cleaning my MAF again, even though it was just cleaned in November and I don't hardly drive the truck. But the last three or four trips I took it on, were all pretty dusty. Maybe I'll knock out the new air filter too.
All four O2 sensors were changed within the last 3 or so years with Denso. Maybe I just need a new MAF.
I might do a sea foam intake treatment. I've got one in the garage.

 

That's awful Rich of you....

Possible bad crude oil in NM or Gilmer ?

 

It's been on going since I got back to TX. I've cleared it several times over the last few days. Drove 5 hours each way for the Toyota Jamboree. The CEL usually comes on when idling or going slow.

 

In case this helps someone down the line, turns out my Hewitt bypass was the issue. It worked flawlessly for about 3 years, then started making my truck run rich. I removed it and the truck runs great now and passed inspection yesterday.

 

Just a note: Oiled filters are bad, mainly because they contribute to excessive buildup inside the throttle body over time, buildup on the MAF sensor, and other things.

First thing to correct here is your behavior: Stop using oiled filters. Whatever idea you have in your head about why they're some "superior" to Toyota's OEM filter - and mind you, Toyota knows better than anyone what filters are going to perform the best to contribute to the longevity they're known for, so it's best to use their filters, moreso than you, or someone at K&N or similar will know - get those thoughts out of your head. Using oiled filters is like using Afrin to unclog your nose, you may see that initial boost of benefit, but over time and continued use, you're actually clogging your shit up worse. Only major difference being, when you remove the oiled filter, the microscropic droplets of oil residue that have since coated your MAF sensor and throttle body, throttle plate, etc. DO NOT go away. At least with something like Afrin, your passageways rebound with time.

Ditch the filter. And if you've bought into the hype of "cold air intakes" in the application of our trucks using the 4.7L or 5.7L ... stop. Get help. Those companies will show you the initial results you get, but they fail to show you what continual use does to the engine.

Always OEM filters from a known-genuine source (avoid scAmazon/fleaBay/WallyMart/HomeDepot/other online vendors that allow 3rd party sellers). You can get these from Toyota Parts Program online cheaper. There's actually a 15% off sale going on now, for the next 5 days.

(and yes, I realize @odaflo 's reply is from 4 years ago and he'll probably never read this reply...)