Check Engine Soon question
 

My Check Engine Soon light came on last week. I checked the code and it was P0174, lean bank 2, oxygen sensor. I thought this was related to my resonator removal and so I put my resonator back on and reset the light. I am planning to go on a trip to So Cal. The light has not come back on yet, and I hope it doesnt, but if it does while I am driving, will there be any problems until I get back? Any suggestions. Thanks in advance.:thumbup:

Shouldn't cause a problem in the short term to drive it.

Planning about 1000 miles total for the trip. still any problem?

:bump:

personally, given the code you described, I'd still drive it. But it's your vehicle, so factor in the degree of risk you are comfortable with.

I just want to make sure that it is okay that I did reset the code and that I wont experience any problems.

You have a sensor starting to go bad. As I recall, there's generally 2, so even if one goes then you still should be ok until it's replaced.

That said, there's still a risk, but in my opinion it's not a big one.

You'll be fine..there's 3 or 4 O2 sensors. Is there actually an o2 sensor bung in the resonator? If not, then that sensor is actually going bad..

I reset it for now. If it is serious enough, it should come back on, right? I just dont want any problems on my trip. I will deal with it when I get back, if the check engine light comes back on. This is the first time my check engine light has come on, so I am just making sure.

You won't have any problems. Just reset it.

Thats what I did. :thumbup:

Thanks guys for you help.

There should be 4-O2 sensors, 2 before the cats, 2 after the cats, and all four are located ahead of the resonator. The resonator (or lack of) should not throw an O2 sensor code, since all the readings are taken upstream of the cat.

If you have lean code, that probably indicates an intake leak that is leaning out the mixture. Didn't Cleaner or someone write up an article on diagnosing a 3.0i intake plenum leak?

How would an intake leak, lean out the mixture? Less air= rich.

It depends on where the air leak takes place. What you're saying is true if the leak is in a pressurized area. Is a plenum pressurized?

P0174 OBD-II Trouble Code
Technical Description

System Too Lean (Bank 2)
What does that mean?

Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1.
Note: This DTC is very similar to P0171, and in fact your vehicle may show both codes at the same time.
Symptoms

You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
Causes

A code P0174 may mean that one or more of the following has happened:

• The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled
• There could be a vacuum leak downstream of the MAF sensor.

Possible Solutions

Possible solutions include:

• In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
• Inspect all vacuum and PCV hoses, replace if necessary
• Check for a dirty fuel filter and proper fuel pressure

Of course, if none of this is taking place, it's simply time to replace the O2 sensor(s) as others have suggested.

I am not very good at checking and fixing things myself. Should I head to the dealership then?

I gotcha :thumbup:. Bit of a brain freeze there since I've heard vacuum leak associated with this OBD code many times, but the reasoning just wasn't clicking tonight !ouch:.

I'm no authority especially when it comes to automotive science, so I don't mind the doublecheck. :thumbup:

Where is the MAF located, so I can check it? I am not very good at checking and fixing things. I read through some threads and noticed that people had the Check engine light come on after reseting the code P0174. I had not had this happen to me yet.

My 2001 X5 4.4 threw the same light and code and it ended up being a bad tank of gasoline.

Michael

Did you just reset the light, and it never came back on??

I was driving my X today, and the light did not come back on. I have put on close to 50 miles since I reset it and nothing.