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2006-2009 Range Rover MkIII / L322
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Discussion Starter · #1 ·
Hello Everyone,

My 06 Range Rover HSE is up to its schenanigans again. It is only throwing the error code P0174, and there is a slight odor of what smells like exhaust that comes through the vents and shows up intermittently when at a stop light. I will be replacing all my spark plugs (Was supposed to do this at 100K, but am at 118K now), as well as the Crankcase Emmission Regulating Control Valve. I was wondering if you all had any further pointers on what I should be looking for. The car is not misfiring, nor is it having any issues with acceleration. The catalytic converters appear to be operating properly as well. I am thinking of also replacing the hoses that connect to the Control Valve. Are there any good online sources where I can find this? If not, I will just get them from the dealer as it has been tough to find the correct part numbers.

Any other pointers are appreciated! It is worth noting that this error did not occur until I started to use the AC Compressor on a day that was slightly warmer here in Utah.

Thanks in advance!
 

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PCV P/N is LR003380, no need to replace the tube to it, I haven't seen one fail other then from being broken by being forced off.

The 174, or 171 fault on this engine can be many different, and all somewhat common issues. Anything from fouled spark plugs, vacuum leak, MAFS, software calibration, exhaust leak, bad gas - the list goes on. It is really somewhat throwing parts at it, or chasing a possible issue that may not be there without having the adaptive fuel trim display. This is only available with a dealer level diag system, but will point out exactly what to look for, as it breaks down fuel trims based on engine speed and load, both long term and sub-feedback. With the possibility that the engine could be running perfectly, but throwing the fault due to the calibration file being bad, it is almost worth getting it printed out for the diagnostic charge a dealer(or indy if you have one with this equipment local)

That said, I would probably change out your plugs and PCV(this is a perfect time to replace the ignition capacitor and have an injection service preformed) and see if that takes care of it, as it is due for it anyway.
 

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2006-2009 Range Rover MkIII / L322
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Discussion Starter · #3 ·
PCV P/N is LR003380, no need to replace the tube to it, I haven't seen one fail other then from being broken by being forced off.

The 174, or 171 fault on this engine can be many different, and all somewhat common issues. Anything from fouled spark plugs, vacuum leak, MAFS, software calibration, exhaust leak, bad gas - the list goes on. It is really somewhat throwing parts at it, or chasing a possible issue that may not be there without having the adaptive fuel trim display. This is only available with a dealer level diag system, but will point out exactly what to look for, as it breaks down fuel trims based on engine speed and load, both long term and sub-feedback. With the possibility that the engine could be running perfectly, but throwing the fault due to the calibration file being bad, it is almost worth getting it printed out for the diagnostic charge a dealer(or indy if you have one with this equipment local)

That said, I would probably change out your plugs and PCV(this is a perfect time to replace the ignition capacitor and have an injection service preformed) and see if that takes care of it, as it is due for it anyway.

Thanks again Dave for the thorough reply! I will definitely look into replacing the ignition capacitor as well.
 

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Discussion Starter · #4 ·
Hi Again,

Well the P0174 code keeps showing up and won't go away. Here is what I have done so far:

1. Replaced all spark plugs.
2. Replaced PCV Valve
3. Replaced Gas Cap
4. Removed and cleaned the MAF Sensor
5. Cleaned the air intake at the throttle
6. Replaced ignition capacitor

Do you all have any other pointers? The car seems to be running perfectly and isn't experiencing poor fuel consumption either.

Thanks in advance!
 

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It is really somewhat throwing parts at it, or chasing a possible issue that may not be there without having the adaptive fuel trim display. This is only available with a dealer level diag system, but will point out exactly what to look for, as it breaks down fuel trims based on engine speed and load, both long term and sub-feedback. With the possibility that the engine could be running perfectly, but throwing the fault due to the calibration file being bad, it is almost worth getting it printed out for the diagnostic charge a dealer(or indy if you have one with this equipment local)
See above.
 

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2002-2005 Range Rover MkIII / L322
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I thought I read that some people have had cracked exhaust near the cats and getting it welded solved their problem.
 

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That was mostly on 03-05s, and would cause a P1171/4 when read on a generic scanner. However, an exhaust leak can cause a lean code on this engine as well.
 

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Discussion Starter · #8 ·
That was mostly on 03-05s, and would cause a P1171/4 when read on a generic scanner. However, an exhaust leak can cause a lean code on this engine as well.
Hi Everyone,

Well the mystery is solved. When my transmission was replaced, the driver side exhaust coupling was not completely sealed, and it caused an exhaust leak, therefore leading to the lean code. The unfortunate part is that it took a 400 mile drive to find this out. I started to smell exhaust coming in through the vents, and this was the first time I had gone on a drive longer than 30 minutes in the car since the job was done back in January. It also turns out that my light headaches, and occasional fatigue while driving was caused by a mild form of carbon monoxide poisoning. During my long trip, I started to get a horrible headache that would not go away with the normal dose of Alieve D with Sudafed, and that is when I pulled over and thought I smelled a pronounced amount of exhaust in the cabin when the car was not in motion. I left the car running and got out and opened the hood. The exhaust smell was overwhelming in the engine bay.

I then got under the car, and noticed the exhaust coupling on the driver side was not sealed in the same way as it was on the passenger side. I then took out my tools and tightened it up, and the P0174 code is gone. Also, little by little I am noticing I have more energy and the headaches are gone. Thankfully this didn't continue to the point where serious damage was done!

Thanks to all for the input!
 

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I'm replying to this thread hoping Dave (or somebody else) will put an end to my forum searching / googling !!!`)

I've had a few codes since buying this car about a month ago .
I have been gradually doing my normal used car "post purchase service" and as of yesterday had only 420 and 174 remaining .

Today I changed the ignition (radio suppressor) capacitor and pcv valve as the final 2 steps of what I consider to be a "service" .

After unplugging the battery for an hour or so , I went to do a 30 minute parking lot driving lesson with my girlfriends daughter and after this I checked and we have only a 174 pending .

I will take another drive tomorrow to see if it develops into a cel or if the 420 comes back .

I did a quick visual of all inlet hoses and everything seems good , and I don't see any leaks on the exhaust .

Although I consider the MAF to be a consumable on all modern engines , I have not replaced that yet as I don't consider it a "service" part and although it's only $180.00 I don't want to simply throw money at it hoping for a result !!

My next step is a visit to the dealer for a new expansion tank and level sensor as I'm still getting a "check coolant" after replacing the thermostat last week , and I plan to get the diagnostic read-out Dave talks about .
Will it/they tell me where to look next or do I need to share the printout on here ?

Am I right in thinking a 174 narrows it down to one bank of cylinders ?
Am I also right in thinking (like most modern cars I have had) ANY issue with the coolant sensors will throw an unrelated code ?
 

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So about an hour ago we went out to lowes .
Did a check in the parking lot and now I have zero codes , pending or full .
Just got home and checked again , zero codes pending or full .

Hopefully it will stay this way and a service worked to clear the faults . :D
 

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A cel popped up yesterday afternoon after the car was driven all day .
The p0174 is back !! :(

Time to visit the dealer for a diagnostic ...
 

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2006 L322 / 4.4 / 118K miles

With this same code (and PO171 I believe) I went through a lot of diagnostics; replaced the MAF and PCV... leak check intake air ducting etc. I ended up with a simple fix by accident. As a creature of habit, I always gassed up at the same station on the way to work. I took a quick trip across the state and after a fill up out on the road, my code vanished. Hmm. So I changed stations at home and that code has never popped again.


My usual station was a Shell.... One of the stations that has gas that my RR likes is also a Shell... the attendant told me that refinery brands are fairly consistent, but the station owners may mix and match a bit... some branded stations sticking strictly to the brand and other branded stations fudging and mixing wholesale when available. I guess it depends on the owner of the station. One way or another, I've identified a few stations around my area that consistently pump gas that my RR likes. I was glad for a simple fix. Might be worth a try .
 

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After moving house around a year ago I started having cel problems on my Carrera .
I am under the impression that in SoCal at least it is better to gas up at a "frequent user station" such as costco , as the closer you put gas in to a freeway the more likely you are to have problems (300 miles away you get a cel so you're less likely to think of the gas . Or return there )
That's a different story entirely , but the rover was filled up at a shell garage around the corner from the dealers after collecting the pcv and capicitor on Friday afternoon and the cel stayed off until Monday afternoon ....
This this evening I checked again and both the 174 and 420 both showed and turned into a cel .
Off to the dealers after work tomorrow for a fuel trim diagnostic ....
My local dealer is also the nearest BG injection/inlet service dealer , so that is handy should that be the next course of action :)

You mention a 171 as we'll , and that is something I have been thinking about ... The MAF is shared between both banks , so if it was a bad MAF or leak between that and the "split" I should also see the same code on both banks ???
 

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oooo good topic.
We have very bad and dirty gas in Kazakhstan.
I have DTC P0170
will check today exhaust pipes for leaks.
I have already big coolant leak problem.
how much does its cost the
ignition capacitor? and the part number please.

i been told in Land Rover Center the DTC code reading by my own OBD Scanner is not excat code. They said i have misfire on 8. cyclinder

I read very good tips on this topic. thank you guys
 

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It's 25.11 at my local dealers .
I'll get the part number later off the box but I believe there are two versions for sc and na
 

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A quick update .
Whilst it was there I instructed them to BG clean the inlet and injectors (275) but when I got there the technician didn't print the fuel trims and another guy was now using the laptop so the data had gone .
We have to try again next week .

So I picked up the MAF (175) and hood struts (90) I'd ordered , and installed them when I got home ...

I pulled the "REMAN" bar code sticker off the MAF that was already on the car , and underneath was a Toyota sign and part number !!!

Car doesn't seem to be running any better , but I thought it was fine anyway , and the 174 code has now gone .
I don't know if this was due to the inlet and injector clean or the MAF .
I could/should have waited before I put the new MAF on to find out and report here , but ever since we got the car and I saw that remanufactured barcode sticker on the MAF I have been itching to get it off !! :)

Still getting a 420 code , so I'm going to take a longer look for exhaust leaks today , although from under the hood no side seems louder than the other and I cannot hear anything when putting my head under the car on either side .
 

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I just got this P0174 code a few days ago. Then it went away last night. Has not turned back on since.

Only things I can think of that I did right before the code is:

I put 91 oct in it (still premium just not the 93 stuff...but I have been putting in 91 since I got the Range a month ago).

And when I filled up I have a habit of rounding up to the next dollar when the pump shuts off after being full. And this time I put in almost a full dollar to round up after the pump stopped. Is this car that sensitive that topping it off too much would cause this?
 
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