My ghost codes p0171 and p0174
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
My ghost codes p0171 and p0174
Hello.
I've had some "ghost codes" in my car for a while now. It is p0171 and p0174. The car runs just fine, idles fine and seems to be in allright condition. It may surge a little when driving speeds of 110-130 kmh.
These codes can come and sometimes go away without me interfering. Last time I got the codes was maybe 4-5 months ago and they went away 1-2 days later. Yesterday they were back again. The codes seems to appear when the car is idling, reversing or driving at veeeery low speeds. I had some problems with my oil cooler and was losing oil and coolant. That is fixed (probably not related to the codes at all). I have had a smoke test and the engine is sealed. Spark plugs are changed, oil and filter is new.
What can I do now? I want to first take a test of my MAF and 02 sensors to see if everything is ok without just replacing the parts if they are working just fine. Is this possible? Any suggestions.
Hope some of you guys can help me
I've had some "ghost codes" in my car for a while now. It is p0171 and p0174. The car runs just fine, idles fine and seems to be in allright condition. It may surge a little when driving speeds of 110-130 kmh.
These codes can come and sometimes go away without me interfering. Last time I got the codes was maybe 4-5 months ago and they went away 1-2 days later. Yesterday they were back again. The codes seems to appear when the car is idling, reversing or driving at veeeery low speeds. I had some problems with my oil cooler and was losing oil and coolant. That is fixed (probably not related to the codes at all). I have had a smoke test and the engine is sealed. Spark plugs are changed, oil and filter is new.
What can I do now? I want to first take a test of my MAF and 02 sensors to see if everything is ok without just replacing the parts if they are working just fine. Is this possible? Any suggestions.
Hope some of you guys can help me
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,152
Likes: 1,766
From: Colorado
G550
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Trending Topics
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
low fuel pressure
Hello.
I've had some "ghost codes" in my car for a while now. It is p0171 and p0174. The car runs just fine, idles fine and seems to be in allright condition. It may surge a little when driving speeds of 110-130 kmh.
These codes can come and sometimes go away without me interfering. Last time I got the codes was maybe 4-5 months ago and they went away 1-2 days later. Yesterday they were back again. The codes seems to appear when the car is idling, reversing or driving at veeeery low speeds. I had some problems with my oil cooler and was losing oil and coolant. That is fixed (probably not related to the codes at all). I have had a smoke test and the engine is sealed. Spark plugs are changed, oil and filter is new.
What can I do now? I want to first take a test of my MAF and 02 sensors to see if everything is ok without just replacing the parts if they are working just fine. Is this possible? Any suggestions.
Hope some of you guys can help me
I've had some "ghost codes" in my car for a while now. It is p0171 and p0174. The car runs just fine, idles fine and seems to be in allright condition. It may surge a little when driving speeds of 110-130 kmh.
These codes can come and sometimes go away without me interfering. Last time I got the codes was maybe 4-5 months ago and they went away 1-2 days later. Yesterday they were back again. The codes seems to appear when the car is idling, reversing or driving at veeeery low speeds. I had some problems with my oil cooler and was losing oil and coolant. That is fixed (probably not related to the codes at all). I have had a smoke test and the engine is sealed. Spark plugs are changed, oil and filter is new.
What can I do now? I want to first take a test of my MAF and 02 sensors to see if everything is ok without just replacing the parts if they are working just fine. Is this possible? Any suggestions.
Hope some of you guys can help me
check your fuel pressure... tired pump/filter.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Can it have something to do with the high pressure fuel pump, it has always been noisy according to a friend of mine. Also, can the fuel pressure result in surging? Is the MAF to be suspected too?
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
PRESSURE READOUT
Thanks for your reply! Going to get my gearbox serviced next week and told my mechanic to also check the condition of the o2 sensors. I can also ask him to check the fuel pressure. If something is not right, is it an easy fix?
Can it have something to do with the high pressure fuel pump, it has always been noisy according to a friend of mine. Also, can the fuel pressure result in surging? Is the MAF to be suspected too?
Can it have something to do with the high pressure fuel pump, it has always been noisy according to a friend of mine. Also, can the fuel pressure result in surging? Is the MAF to be suspected too?
One thing is causing this right now. Not 25 different parts for no results.
My money is on fuel tank supply pump pressure us limited by dirty filter.
Lambda and MAF low down the list.
You're going to find RICH TRIMS asking for fuel.
Take 5mn to read out FUEL PRESSURES LOW + HIGH with your handy $150 scanner.
cake walk?
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Exactly, these are all good questions to answer with the process of troubleshooting.
One thing is causing this right now. Not 25 different parts for no results.
My money is on fuel tank supply pump pressure us limited by dirty filter.
Lambda and MAF low down the list.
You're going to find RICH TRIMS asking for fuel.
Take 5mn to read out FUEL PRESSURES LOW + HIGH with your handy $150 scanner.
cake walk?
One thing is causing this right now. Not 25 different parts for no results.
My money is on fuel tank supply pump pressure us limited by dirty filter.
Lambda and MAF low down the list.
You're going to find RICH TRIMS asking for fuel.
Take 5mn to read out FUEL PRESSURES LOW + HIGH with your handy $150 scanner.
cake walk?
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Exactly, these are all good questions to answer with the process of troubleshooting.
One thing is causing this right now. Not 25 different parts for no results.
My money is on fuel tank supply pump pressure us limited by dirty filter.
Lambda and MAF low down the list.
You're going to find RICH TRIMS asking for fuel.
Take 5mn to read out FUEL PRESSURES LOW + HIGH with your handy $150 scanner.
cake walk?
One thing is causing this right now. Not 25 different parts for no results.
My money is on fuel tank supply pump pressure us limited by dirty filter.
Lambda and MAF low down the list.
You're going to find RICH TRIMS asking for fuel.
Take 5mn to read out FUEL PRESSURES LOW + HIGH with your handy $150 scanner.
cake walk?
These reading are probably too high?
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Yes, exactly!
High LTFT confirms my previous post.
Now read your fuel pressure.
Note fuel trims are unbalanced.... so something additional may be involved.
High LTFT confirms my previous post.
Now read your fuel pressure.
Note fuel trims are unbalanced.... so something additional may be involved.
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Highly appreciate it! I was in a bit of a hurry when looking at the readings, but I could not find the fuel pressure data (cheap ODB Bluetooth) . You can only speculate, but what is the most likely part(S) to cause this? My car is going to the shop April 4th, will keep you updated on what the verdict is.,
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Highly appreciate it! I was in a bit of a hurry when looking at the readings, but I could not find the fuel pressure data (cheap ODB Bluetooth).
You can only speculate, but what is the most likely part(S) to cause this?
My car is going to the shop April 4th, will keep you updated on what the verdict is.
You can only speculate, but what is the most likely part(S) to cause this?
My car is going to the shop April 4th, will keep you updated on what the verdict is.
That clearly means your ignition is good and your lambda are working.
Diagnose/repair the fuel delivery first then see what happens to the imbalanced value. I think these are two distinct issues.
I am guessing fuel pump filter is packed shut.
🤞
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Your high LTFT say the engine is not getting enough gasoline or too much air.
That clearly means your ignition is good and your lambda are working.
Diagnose/repair the fuel delivery first then see what happens to the imbalanced value. I think these are two distinct issues.
I am guessing fuel pump filter is packed shut.
🤞
That clearly means your ignition is good and your lambda are working.
Diagnose/repair the fuel delivery first then see what happens to the imbalanced value. I think these are two distinct issues.
I am guessing fuel pump filter is packed shut.
🤞
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
It's time to use a smoke machine to look for leaks.
MBWorld Fanatic!
Joined: May 2018
Posts: 6,600
Likes: 6,547
From: Jakarta-Indonesia
2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
02. The pressure is from a scanner ( at fuel filter pressure sensor ) or using another mechanical gauge at the engine bay fuel fitting Tee ?
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Thanks for the answers. He did a smoke test a couple of months ago and did not find any leaks. Not sure how he tested the fuel pressure though. Will ask for the readings next time
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
Maybe it's unrelated, but I randomly checked emission status and got a FAIL on the catalyst.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
confirm fuel pressure yourself
You have lean faults and you reported your mechanic tested fuel pressure and intake leaks.
In addition you're getting catalytic monitor incomplete.
You're now suspecting PCV or plastic cam plugs.
-----
At this point... I would take 5mn to read your fuel pressure for yourself before considering PCV replacement job.
Use your scanner to check fuel pressure both at base idle and also under engine demand to validate filter is not saturated by tank particulate.
You can ignore catalytic status because engine management is unable to run normally. After faults are fixed cats will get a chance to burn off contaminants better.
In addition you're getting catalytic monitor incomplete.
You're now suspecting PCV or plastic cam plugs.
-----
At this point... I would take 5mn to read your fuel pressure for yourself before considering PCV replacement job.
Use your scanner to check fuel pressure both at base idle and also under engine demand to validate filter is not saturated by tank particulate.
You can ignore catalytic status because engine management is unable to run normally. After faults are fixed cats will get a chance to burn off contaminants better.
Last edited by CaliBenzDriver; Apr 14, 2024 at 02:10 PM.
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
You have lean faults and you reported your mechanic tested fuel pressure and intake leaks.
In addition you're getting catalytic monitor incomplete.
You're now suspecting PCV or plastic cam plugs.
-----
At this point... I would take 5mn to read your fuel pressure for yourself before considering PCV replacement job.
Use your scanner to check fuel pressure both at base idle and also under engine demand to validate filter is not saturated by tank particulate.
You can ignore catalytic status because engine management is unable to run normally. After faults are fixed cats will get a chance to burn off contaminants better.
In addition you're getting catalytic monitor incomplete.
You're now suspecting PCV or plastic cam plugs.
-----
At this point... I would take 5mn to read your fuel pressure for yourself before considering PCV replacement job.
Use your scanner to check fuel pressure both at base idle and also under engine demand to validate filter is not saturated by tank particulate.
You can ignore catalytic status because engine management is unable to run normally. After faults are fixed cats will get a chance to burn off contaminants better.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
I can't find the fuel pressure levels on my bluetooth scanner. I would like to see how the readings look because I want to solve this problem now.
However, I got interested in the PCV because that can throw a P0171, P0172 code in addition to my oil loss.
It is very rare, but sometimes when driving in higher speeds at longer distances I can smell a little sulphur/egg probably from the cat.
Is this because there is too much oil getting burned, and the cat is unable to properly take care of it?
However, I got interested in the PCV because that can throw a P0171, P0172 code in addition to my oil loss.
It is very rare, but sometimes when driving in higher speeds at longer distances I can smell a little sulphur/egg probably from the cat.
Is this because there is too much oil getting burned, and the cat is unable to properly take care of it?
I don't think it will directly help your two lean fault codes.
The non-turbo W212 V6 gasoline engines use a simplistic PCV system that burns quartz of oil through the intake. This is a commonly known issue caused by high blow-by.
You may want to use an "MB Approved" 5W40 oil instead of a less viscous 0W40.
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 53
Likes: 4
From: Oslo, Norway
W212 E350, W208 CLK320
You can replace the PCV and the cats but
I don't think it will directly help your two lean fault codes.
The non-turbo W212 V6 gasoline engines use a simplistic PCV system that burns quartz of oil through the intake. This is a commonly known issue caused by high blow-by.
You may want to use an "MB Approved" 5W40 oil instead of a less viscous 0W40.
I don't think it will directly help your two lean fault codes.
The non-turbo W212 V6 gasoline engines use a simplistic PCV system that burns quartz of oil through the intake. This is a commonly known issue caused by high blow-by.
You may want to use an "MB Approved" 5W40 oil instead of a less viscous 0W40.
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
0/5W-40
Look at your owners manual for oil specifications.
Your local MB specialist knows what works best, right?
