P0171,P0174 codes
#11
12-29-2017, 07:02 PM
I reset my engine adaptations, cleared all the codes, ran another bottle of 44K in the fuel and drove that drive cycle plus about 400 miles of highway driving. The car just passed smog and has no check engine light or transmission fault error for the first time in 4 years. At last I can get a current registration sticker on it! It is also doing 17 mpg now, previously it was getting less than 11 mpg.
Success :-) :-)
Success :-) :-)
#12
01-08-2018, 12:51 PM
Worked for me too!!! Still no error codes and I passed the emissions/smog test! Issue seems to be completely resolved and the engine is incredibly smooth. I added gasket maker to the flimsy metal gaskets #3 and #4 in the attached diagram, then tightened bolts on #5 at the back right of the engine bay.
Last edited by kels83; 01-08-2018 at 01:08 PM. Reason: Added diagram.
#14
03-31-2019, 07:42 PM
#15
01-27-2020, 10:40 AM
This has been a very helpful thread. I decided I wanted to try a smoke tester aka automotive houka so I purchased one off eBay. It proved to be invaluable. In order to get smoke through the entire system, I covered the top of the air filter with plastic wrap and drilled a small hole on the top of the housing which I later plugged. Once the system is pressurized after a few minutes, 4 leaks were identified. Both ends of the hose off the PCV valve on the right valve cover and the longer hose was leaking at the left valve cover. There were also leaks at the EGR valve. I ditched the gaskets, sanded the mating surfaces and applied sealant but replaced the PCV valve hose but applied sealant to the leak at the right valve cover. Earlier, I had replaced the gaskets around the VVT solenoids. No more P0171 and P0174. Of course, in my haste, I took apart the top of the EGR valve and applied sealant where it wasn’t needed and f’d it up. Now I have a new CEL for the EGR valve and a need a new one if I can’t get it properly cleaned of sealant. Sealant is messy and once it cures, gets very gummy and is difficult to remove. Any hoo, fun little exercise but a bit frustrating trying to chase down these leaks. If your ride is running well and you’re getting one or both of these codes, it’s and EGR or vacuum leak somewhere. The likelihood of the problem being on the fuel side is low if the 3 is running well, IMO.
Chairs (LOL)
Ravi
Chairs (LOL)
Ravi
#16
01-27-2020, 11:37 AM
#17
01-27-2020, 05:06 PM
Camel Trophy
#18
01-28-2020, 11:19 AM
I got a new hose from the PCV valve to the intake. I then applied sealant to the hose end of the hose which goes to the left valve cover. Not counting on it lasting forever but at least I’ll know where to look. If your hoses aren’t cracked, you could change the O rings and see if that does the trick or apply gasket sealant like I did.
I ordered a used EGR valve off eBay today so I can replace the one I hummed up with sealant.
I ordered a used EGR valve off eBay today so I can replace the one I hummed up with sealant.
#19
08-24-2021, 02:18 PM
LR3 with the same codes
I am new to the forum so posting this to relate my experience with the lean codes on Lr3.I have an 08 Lr3 with 64000 miles. While driving one day check engine light goes on, ran the codes and came up P0171 and P0174, looked for obvious leaks and find any. I looked for info on this forum and decided to clean the maf sensor , light comes on after a few miles. Decided to change o2 sensors,long story short the upstream sensor passenger side had to be torn out of the pipe get anew nut welded in and then replace the sensor, the bolt holding converter to manifold had been put in bent so that was also a pain to remove. So new sensors, light still comes on, next I replaced the pcv valve, no help. After spending 2 weeks to figure this out I removed all the click connectors on pcv hoses to tight rubber hose clamps to eliminate any pcv leaks, I sprayed penetrating oil along throttle body gasket and this went on both sides of the gasket meaning that is where the air leak was. I took the throttle body off and applied loctite 515 sealant on both sides of the gasket and reassembled the throttle body and cleared the codes again .The codes have not shown up again, during the process I noted that there is a lot of vacuum in the throttle system and any minuscule air leak will set off the codes. I did not need to replace any of the other parts but replacing them is getting me 23 to24 mpg on highway driving and about 15 mpg in town so I guess it was worth the changes . I hope this helps people who have had these codes.The throttle body gasket is the leak.
My air conditioner stopped blowing air last week in my 2006 Lr3 and the check engine light came on. I took it to get coded and got the same codes as you. P0171, P0174. Was your A.C. effected by the problem? The printout I got said it was most likely the Intake Air Duct. I just wanted to do some research before I start replacing things.
Thread
Thread Starter
Forum
Replies
Last Post
cipher982
Discovery II
5
02-27-2013 08:59 AM