My 03 disco (71k miles) just recently decided to spit out the Service Engine Soon light. I went out and purchased an OBDII scanner and it gave me back a P0174 code. Tracing back to when the light first came on, I decided to check the gas cap for any leaks and noticed that it was very loosely fitted. I tighted the cap and the light went off.....come 10 miles later the light is back on and the gas cap is tightly fitted. 7k miles ago I completed: Magnecor and +4 bosch wires and plugs, replaced air filter(paper), induction cleaning, throttle body cleaning, added sea foam additive to fuel tank, changed t/case oil.

About a month ago I noticed that the exhaust manifold to pipe connection was loose and it was leaking alot of exhaust, so instead of putting a new gasket in, i decided to just tighten the bolts....worked fine, but could this be the reason?

I read alot of threads on here in reference to P0174 code but it looks like everyone is getting the code in addition to others. This is the ONLY code I've been getting. Anyone have any clue as to what it could be? Thx so much for your help.

Oh yeah, forgot to add that the exhaust smells rotten (like boiled eggs) and I don't get squat for gas mileage.

 

P0174 and p0171 are usually a bad MAF. (Mass airflow sensor.)

 

how many miles are on your truck? have you replaced the o2 sensors or catlytic converters yet? the eggs smell could be caused by a failing or failed cat. get under your truck with it off and tap both cats with a block of wood. if you here some rattling the cats need to be replaced and when you replace the cats do all 4 o2 sensors.

 

71k miles on the truck. I've never replaced the o2 sensors or the cats yet. I'll test out the cats when I can find a plowed/dried area in my parking lot. I'm in Fairfax, VA, and after that snow storm, I haven't even seen a snow plow in our neighborhood. I'll swear by the Nitto's....pulled 2 people out already. So if its not the cats, then can I assume the MAF is bad? Thx for your help.

 

Lets make it simple, a 174 indicates that you bank 2, passengers side, is running lean. Didn't your new scanner tell you that?
Don't go throwing parts at it till the problem is found, it is not a gas cap, acts or 02's until you get an additional code indicating so.
When you get a chance, drive it hard, full throttle acelerations and try and force out any other fault codes. If you get another code, get back to us.

 

Yes, my scanner did tell me that....I was under the assumption that people on this board already knew that.....as to what that (bank 2 running lean) means, i have no idea. So if i run it hard and i don't get any other codes, can i assume that everythings ok?

 

richief556,
i just want to throw this out there real quick... it may be irrelevant. i'm down in charlottesville and went through the same snow storm. i just got the same p0174 and i got a terrible exhaust smell.

i was using 4 wheel low a lot over the past few days. i also noticed that i was really (embarrassingly) low on oil.

after i checked the code at advance auto today, the ses light hasn't come back on. also, i changed out the maf sensor earlier this year. so, i doubt that it's the maf.

just throwing that out there. i don't know anything about this stuff.

 

yeah if its cleared and you don't throw any codes in the next drive cycle, you are OK for now. eventually whatever the problem is will surface again with more codes.

 

If you want to try and clear it, that is fine, if it comes back you stand the possibility of valve and or cat damage so it does need to be addressed ASAP.

 

yoface79 - thx for the tip. Did you really even need it in 'low'?

I still have yet to see any other codes come out after I've driven it hard. I also just happened to notice after driving it hard this past weekend.....while driving thru the remnants of large caps of snow through my unplowed lot i noticed a "clunking" noise. look under the car and see my (yellow) OME shock sticking out underneath the rear axle. I installed the lift 4 months ago and I'm wondering how the hecht did the bolt jar loose?! I ran over to parts at Landrover yesterday (as they were closed most of the holiday week/end), and they told me they would have to order the part...$30 for a bolt and nut!! I said "no thanks" and ran straight over to Lowes....$5.25 total for M-12 nut and bolt! Has this happened to anyone before?!