I'm not seeing a lot of intel on the P0174 code. I'm getting each time I make the 3 hour drive to see my mom. Each time it's about 20 min after refueling and about 2 hours into the drive.

Is the the gas cap code? Strange that I do not get it around town after refueling.

 

https://www.clublexus.com/forums/rx-...and-p0174.html

It can be the gas cap or many other things. Vacuum leak is one. MAF sensor is another. It means the computer has detected a lean condition. I solved mine by replacing the MAF. I tried cleaning with no success. They do go bad.

 

P0174 code alone means only 1 bank is runing lean.
In this case it's the front Bank(radiator side)
I don't think it would be a gas cap problem since that would throw an evap code like a P0440,442,441 etc..

Few possibilities:
1. A/F sensor just in the boundary threshold of long/short term fuel trims.
2. If there was a vaccum leak, it would be around the injector area of that Bank alone. intake manifold gasket also but highly unlikely.
Remember only P0174 code is thrown and not both P0171,174.
3. Partially clogged injectors of bank 2.

There are more poss. but I'm leaning towards a new A/F. Only being it happens while cruising(light load).
If you happen to have a Scan tool that reads A/F sensor voltage. You will see slight diff reading in them.

FWIW...I had a P0171 code and replaced the A/F sensor and fixed it. Funny 3 months later the 174 code came and I also replaced that A/F and no issues since.

I think 171 is more common since it's the back bank and it gets hotter there more than the front bank.

 

Bank 1 would be the side close to the firewall ... away from the radiator. Please correct me if I am wrong.

Salim

 

Yes.
Bank 1---Firewall side
Bank 2---Radiator side

 

Thanks guys!

I replaced the Bank 1 Sensor 1 about 6 months ago so it may be time for the other. I'll keep monitoring...

 

OE or aftermarket?

 

Good call, it was OE though...

 

Hey, from what I've seen.....This code (P0174) is on the bank 2 side and not the bank 1?

 

^^Yeah...where in this thread, or anywhere else, did you see P0174 is in bank 1?

 

Yep, bank 2, radiator side.

 

Nad1370,

First, thanks for the help. I misread "1 bank is running lean" as bank 1. I was on my blackberry when I read it and misread it. I also saw some talk from salimshah about bank 1, again from my blackberry so I assumed that is where guys were going.

I'll continue to monitor, this code doesn't pop from everyday driving. It only pops on long road trips.

When I had the bank 1 sensor 1 go out, I would get the P1130 & P1135 code every time I drove the car.

 

No problem
For a minute there I thought I had my "banks" confuse. lol

My P0174 code was also intermittent for a couple of months.
Then one day it just finally gave up.
ehhh...nothing last forever in these vehicles.
Just got to fix whats broken and not let it get worse.

 

This is informational only (for the not-so-highly-mechanical-knowledgeable). There are 2 major OBDII sites that have the wrong information for DTC P1155. I can only assume they have somehow gotten the incorrect info from T/L because the exact same misinformation is on both sites. It SAYS B1S1. That is incorrect for P1155. It SHOULD be B2S1. I even used the "correct a mistake" feature a few months ago and it has never been changed so I assume they thought the factory couldn't be wrong, so I must be. Was trying to avoid confusion for those not "highly" knowledgeable, but I guess it didn't work.

 

Update:

Started getting this code a little more frequent. Replaced (OEM) the Bank 2 sensor 1 A/F sensor. Code has not returned.