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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #1
Hi,
I had a shop replace the O2 sensors in the car, all 4 brought from trusty online rover parts we site.
Now i am getting
P0133/153
And
P0171/174

Bank 1 or 2 lean and,
Bank 1 or 2 slow response.
One or the other after clearing codes.

They shop replaced the front bungs on both banks. I think they didnt install the sensors at the same depth. Any thought?
I will clean the throttle body later and have done that service about 30k miles ago.

Is there any drawings of how deep the sensor should be installed? I don't want them to experiment anymore.

You help is kindly appreciated.
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #2
Ok so I got the slow response fixed.
Now I just have p0171/174
So i am looking at this thread for help. https://www.rangerovers.net/forum/index.php/#/topics/330950?page=1

I already checked the attached pipes. All the suction there.
1. Need to check PCV line, it was hard to remove.
2. Do I Need to see if PCv is working, but how?
3. What is the hose connected to the top of the throttle body?
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #3
Removed the pcv line and valve, no leak in the line.
Cleaned the valve with brake cleaner.
 

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2013-2015 Range Rover Sport
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159 Posts
If you are just having lean faults P0171-p0174 then look for an air leak (past MAF sensor but before o2s) things to check are, bad pcv (cracked diaphragm), cracks in the elbow duct for the throttle body from air filter (check for cracks on the corrugation), hairline cracks in the exhaust before the cats, cracks or leaks at the bung they installed for the 02s, intake gasket leaks. You can test for leaks before the engine with brake or carb cleaner and watch for idle change or to be specific watch short term fuel trims on the scan tool. Could also be a bad MAF sensor driving it lean. Leaks in the exhaust can be found with either a stethoscope or by feel with your hand (dont burn yourself it hurts)
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #5
So I cleaned the maf and replaced the pcv valve. My gas mileage has significantly improved but I still get the lean codes.
If I drive only on the highway the mileage is pretty good, up there 16 average.
But in stop and go traffic I was doing 13.5 before the maf and pcv replacement.

The only pipe I have checked for a leak is this one. Do you know what that is?
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #6
I think my MAF sensors dynamic response has slowed thats why in stop an go driving it is not able to reach equilibrium, but at consistent rpms it does.
 

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that hose comes from your fuel vapour purge tank. It should be sitting perfectly square on the nipple fitting.
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #8

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #10
yes i determined i have an issue for sure. 10-12% long term trim.
whats interesting is when i idle after a drive the O2 sensors fall to 0V. so i am assuming they are fairly sensitive as far as 0V and .8V are concerned because only 10% FT can correct the issue. I checked all the hoses for leaks. i need to take it in i suppose?
Any suggestions before i do?


2019_02_28 9_56 AM Office Lens.jpg 2019_02_28 9_59 AM Office Lens.jpg
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #11
If you got lean codes, change the MAF.
Fixed the problem, even after I cleaned the heck outta the original with alcohol aerosol.
60% difference in fuel trims.
Go with the denso
160k miles
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #12
So the maf sensor fixed the issue at first. I did about 150 miles without it coming back. Now lean codes came back twice more one after the other. I was looking through some info on my scanner and found these tests are remiss on what seems like a barely higher than normal adc reading. Can you help with what they mean?

So what have I done so far:
Changed pcv
Changes maf
Replaced o2 sensors (all)
Smoked intake (no leaks)
 

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2006-2009 Range Rover Sport
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198 Posts
Discussion Starter #13
Ok I see the numbers in the last post are just the count that cause CIL to go on.
Now I think I know why it's going on. It's counting the number of times something unexpected happens.
I think that unexpected thing is my O2 sensors are falling below a certain value ~
0.1V. see attached. {Happens when I lift off the gas.}

I think that's the last thing I need to fix.

My evap test at .02" are middle of the road. I don't know what that means.
Besides that car is running great, the trims have adjusted even better now.
 

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Discussion Starter #14
Think it's a sticky egr. Does anyone have diy instructions on how to replace egr valve?
 

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