OBD-II Nightmare (Can't Pass Inspection...)

RealRitzcracker

New Member
Joined
Feb 20, 2013
Location
Raleigh
Hey guys I was wondering if anyone could help me out.
My car is currently 2 years past inspection, the service engine light comes on so they wont pass it.

I scanned my system and have 5 codes.

P0130 – Generic – O2 Circuit (Bank 1, Sensor 1) – MIL ON
P0150 – Generic – O2 Circuit (Bank 2, Sensor 1) – MIL ON
P0174 – Generic – System Too Lean (Bank 2) – MIL ON
P1174 – Land Rover – Lambda Control Adaption Fault Bank 2. Last Occurrence – Maximum Signal – MIL ON
P0171 – Generic – System Too Lean (Bank 1) - PENDING

The O2 sensors are brand new.
From what I've heard it can be 4 possible problems.

1. Air Intake Leak
2. Exhaust Leak
3. Bad O2's or O2 connectors
4. Faulty Injectors

I really need to pass to get my registration so I can stop riding "dirty". I'm in college so I could barely afford the new O2 sensors. It's been about 3000 miles so I know I've driven through all of the drive cycles. Does anybody know a guy who knows a guy who can pass my car for inspection? It would be much appreciated and I would reward with a nice case of beer.
 
A bad mass air will do funny things also
 
What's the year make model trim and engine? I'll run it through my magic 8 ball. Seriously though i have a connection at work that is kind of like a magic 8 ball. That all the active codes it has? Or are a few pending?
 
You should check out scanner danner on youtube! He has a couple great videos that put this diagnosis in a simple few steps. I would see if i could watch the O2 sensors and if they can be made to switch from lean to rich or rich to lean. That will confirm the sensor is working.

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transman731 said:
from the codes i would assume it's a ford.
it' will most likely be a vacuum leak.

we need the vehicle info from this point forward.
Click to expand...
Yeah we need it for idenifix lol... That's what all the young techs want to use as a crystal ball....


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snappy said:
Yeah we need it for idenifix lol... That's what all the young techs want to use as a crystal ball....


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Click to expand...

Lol its so quick... I can read and follow an appropriate flow chart, efficiently too. But it does have quick info on certain checks and tests.
 
If it were only the last three codes, I would be inclined to say that you had a vacuum leak or a Mass Air Flow sensor problem. But those three, combined with the first two leads me in another direction. If the circuits are showing faulty, then the resulting sensors will show lean as well, which might in turn cause a "adaptation fault". I'm not a land rover guy, so that code is new to me, but the lean codes being caused by circuit codes is a condition I have run into before when I work at a Ford dealership a few years back.

The circuit codes are normally bad sensors, bad wires, bad connections, or a bad computer. With the O2 sensors being new, I would be questioning wires that have gotten pinched by other parts, melted by exhaust, or chewed by squirrels (sounds strange I know but I have seen it before). If all your wires are good, and all the connections are tight, then the computer could have gotten fried on two circuits internally (I have seen this happen as well). Did you get OEM sensors from the dealer or did you get el-cheapos from the parts house that aren't a proven direct fit? If you could get a hold of a PCM pinout chart for your vehicle, and a pinout for the O2 sensors, you could eliminate all wires and connectors really simply by running a continuity test with an ohm meter or test light (with the PCM unplugged of course). If you check the wires, and all are good; your O2 sensors are indeed a high quality; I would suspect the PCM. Take this as an opinion, which we all know are like a certain part of anatomy, and make your own conclusions. You may even want to do some internet searching on Land Rover forums to see what others have had as causes for these codes. Others experiences are usually a valuable asset.
 
fordwheelinman said:
If it were only the last three codes, I would be inclined to say that you had a vacuum leak or a Mass Air Flow sensor problem. But those three, combined with the first two leads me in another direction. If the circuits are showing faulty, then the resulting sensors will show lean as well, which might in turn cause a "adaptation fault". I'm not a land rover guy, so that code is new to me, but the lean codes being caused by circuit codes is a condition I have run into before when I work at a Ford dealership a few years back.

The circuit codes are normally bad sensors, bad wires, bad connections, or a bad computer. With the O2 sensors being new, I would be questioning wires that have gotten pinched by other parts, melted by exhaust, or chewed by squirrels (sounds strange I know but I have seen it before). If all your wires are good, and all the connections are tight, then the computer could have gotten fried on two circuits internally (I have seen this happen as well). Did you get OEM sensors from the dealer or did you get el-cheapos from the parts house that aren't a proven direct fit? If you could get a hold of a PCM pinout chart for your vehicle, and a pinout for the O2 sensors, you could eliminate all wires and connectors really simply by running a continuity test with an ohm meter or test light (with the PCM unplugged of course). If you check the wires, and all are good; your O2 sensors are indeed a high quality; I would suspect the PCM. Take this as an opinion, which we all know are like a certain part of anatomy, and make your own conclusions. You may even want to do some internet searching on Land Rover forums to see what others have had as causes for these codes. Others experiences are usually a valuable asset.
Click to expand...
I would think it would have some type of bias voltage that would allow you to unplug the wiring and verify it.

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Hey Guys!

Thanks for all the quick replys.

Its a 2004 Land Rover Discovery II S.

They are Bosch O2's.
There is two I/M Monitors still not ready after 3,000 miles. I believe C and O but I can confirm later tonight when I recheck.
 
Mass air, get a new one from ebay for 65 bucks, it has fixed alot of the rovers at the carlot
 
Usually the valve cover gaskets leak oil that finds its way in to the wiring harness, especially the plugs that hook up to the front O2 sensors. People replace the sensors and the problem doesn't go away because they didn't stop the source of the oil leak and/or they didn't clean up the mess that was already there.

No such value on this vehicle as "baro pressure"

Bad MAF will default to a factory preset fuel trim setting that is "safe" and not lean...
 
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