Greygooser

Hello all-

For the past year, my RX300 has sporadically (every few weeks) given an P0174 (Fuel System Too Lean on Bank 2). I cleaned the MAF sensor and the CEL didn't come back for a longer period of time.

Recently, the P0174 code came back but was accompanied by P0300, P0302, P0304, P0306 codes, which I believe references multiple cylinder misfires (cylinders 2, 4, 6).
I cleared the codes and cleaned the MAF sensor again. I checked the air filter and it appears clean (I also made sure the hose didn't come off the back).

After driving less than 3 miles, the CEL came on again. It was just the P0174 this time.

Any idea what is causing this? I've read many people that get both P0171 and P0174 which indicates a bad MAF. I've read people with misfires replace plugs and/or coils, but I haven't come across someone who's had all these codes together.

salimshah

Welcome to CL

Please read the sticky threads. It is highly recommend to clear all codes and then diagnose the first code you get.

Start here http://www.obd-codes.com/p0174


Salim

Lexmus

On a different car I would get sporadic "too lean" codes. turned out there was a crack in the hose between the air filter and the intake manifold. I fixed that and have had no CEL in over a year.

NotADood

Very common problem, It is usually the bank 2 oil control valve that has gone bad. An easy way to confirm this is to swap between bank 1 and 2.

Bank 1 is firewall side, bank 2 is radiator side.

Greygooser

Thank you, Is this also known as VVT Solenoid? When I googled oil control valve I get a DIY for replacing the VVT Solenoid, and it shows the two locations. I assume thats what you are referring to. In the DIY the two banks are different part numbers, can they be swapped as you suggested? Thanks in advance, I really would like to avoid a costly trip to the mechanic.

salimshah

Check our DIY sticky thread.

Salim

Greygooser

If anyone is interested, after taking it a mechanic he figured out it was the air/fuel sensor on bank 2 was malfunctioning and needed to be replaced. Not cheap, but I never would have figured that out on my own.

Adamcam707

So how would you know if you have fixed the problem or not if you take it to a dealer and they remove the code for you for good or if the code Dosent come back for me that means cleaning the maf and fixing the air leaks was the problem or even if I have fixed it will the code come back?