(Mercedes C230) Trouble Code P0171 - Quick Tips

2004 Mercedes Benz C230K 1.8L
Showing common vacuum leaks on this vehicle.

[@MichaelCWBell]

Great to see and hear that thumb seal demonstration on the hose… that’s an extra dimension of instruction cheers bro

[@suleimanmuhammedhady1198]

I love the method you used plus giving the viewers the values of the trims

[@MrPhoxx7523]

Very well detailed, kudos man, keep up the good work

[@oppongkyekyeku5129]

Wow...what an intuitive video. Thanks a lot Eli

[@figgiefigueroa7372]

Great video! Never mentioned that hose part number. Still thank you 🎉🎉

[@mauricecarson2301]

Thanks for this, it was very helpful

[@whlawson5812]

Anyone having this engine should buy a dashboard mounted OBD2 like Lufi XF. At hot idle of 750rpm with engine selector on D MAF should be 4.5 to 5g per second vs MAP at -7.3psi vs throttle body at 15% open. It can show many parameter like short fuel trim, long fuel trim, exhaust sensor , IAT etc etc. On this OBD2 I stick at small note of 2000 rpm vs MAF of 27g/second at 0 psi of MAP. Occasionally I will put auto cruise at 85km/hr@2000 rpm. On hilly gradient intake air manifold will creep to 0 psi or higher. At exactly 0 psi MAF should be 27g/second. At steep gradient it easily goes up to 37g/second while sometimes keeping to its 5th gear. During early morning, 1st start up of the day, MAF is at 15 to 17g/second as some of air flow goes into secondary air injection for the 1st 45 seconds. I

[@thelufflife8805]

The Master Teacher giving another class of perfection...keep em coming!

[@EliTheOBDTech]

Much appreciated!!!

[@Geezy314]

Great video sir thanks

[@nydrell1969]

Thanks bro good tips

[@Dozinox]

Had my 2005 W211 m271 in three different workshops, and twice at the stealership regarding this code. Nobody seems to be able to find the cause. I've had this issue for many many years

[@Whatdotheyhavetohide]

Thank you!!!

[@EliTheOBDTech]

You're welcome!

[@darkvador55]

This was a very useful video! I got a P0172 code from an autozone scanner and it said to replace my PCV Valve. Do you know if that would cause my C230 to stall out when warm?

[@EliTheOBDTech]

Possibly, since your running rich, computer is taking away fuel.

[@AlexDiaz-iw3zz]

That first hose that you touched where does the other end connect to from the throttlebody mine is just hanging there and i have a p0171 code but i dont know where to connect the other end to.

[@EliTheOBDTech]

It connects to a skinny gray or white plastic.

[@otherander]

Tks for helping...... my is long term fuel trim that is high (24%).... is that vacuum leak too?

[@EliTheOBDTech]

If your fuel trims start high and then drop when raising rpms, then yes.

[@josertafoya]

Hi Eli. Where does the first hose that you showed come from? My hose is missing and and I have the same code.

[@EliTheOBDTech]

There is a vacuum port just behind the electronic idle control actuator

[@josertafoya]

@@EliTheOBDTech Thanks for replying. I see the port there but there is no hose. I'm sure that's why I'm getting the P0171 code. Where should the hose be coming from?

[@EliTheOBDTech]

@@josertafoya It connects to a white or gray plastic hose. It's very thin and it runs to the left side of the engine bay. Don't remember exactly to what.

[@Whatdotheyhavetohide]

Can you do one on the stepper motor that does the annoying clicking from inside the dash?

[@EliTheOBDTech]

If I get the opportunity, I will.

[@jaimesolis5936]

They are all connected

[@MrSoulstealer1]

Im pretty sure mine ended up being the one behing the maf....found it unplugged itself, why? Not sure....but yeah, it came undone on its own...

[@EliTheOBDTech]

That is a mysterious question... how it came undone?.... I don't even have an answer... I'm glad you found your problem.

[@MrSoulstealer1]

@@EliTheOBDTech right? Like i would get it if its because i was smashing on the gas maybe and all the pressure would build and cause it to pop off....but its just been sitting in my garage, and last time i drove it, was to the store and back just cruising. So i have no idea, but i started it up after sitting for about a week and yeah, idle shaking. Glad it was just that, ended up buying spark plugs and switching them out thinking it was something more serious (wanted to inspect the spark cylinders due to 2 years ago the valve cover gasket failed and flooded cylinders with oil resulting in same issue, thought it came back). Luckily all clear, and i guess bright side is its got new spark plugs lol.

[@eduardoa4558]

Hello. On my 2009 C180k, the tube that fits into the throttle valve jumped de repente at 5500 rpm because the clamp broke... 😕 Unfortunately it caused damage to some part. Engine very fails at cold idle. When I start the engine after 2 or 3 hours off and start, that's when the worst happens: the engine very shakes and fails with light acceleration for about 30 seconds.When it warms up it improves, but it continues to fail in idle e when I press the accelerator lightly. There is no loss of power at "full power" acceleration. after an error reset, I have the error code P0172 and it misfires in cylinders 1 and 3. All this just because the compressor tube has come loose next to the throttle valve...Please help me. What's gone wrong?What's your opinion? What could be damaged when the tube came loose?

[@EliTheOBDTech]

Can you send me pics to be sure what tube you are talking about. Send to my email: [e-mail]

[@eduardoa4558]

@@EliTheOBDTech

[@ccampos2989]

Eli I have a loose vacuum connection, that very last hose you plug up with your finger, where does that hose go connected to? It’s a Mercedes c230 Kompressor 2004

[@EliTheOBDTech]

If you stick your finger in the area where I connect it to, you will feel a small vacuum port.

[@ccampos2989]

@@EliTheOBDTech it connects behind the throttle body? Sorry watched the video twice and I didnt see you connect any hoses to anything

[@EliTheOBDTech]

@@ccampos2989 Yes, vacuum port on the throttle body.

[@ccampos2989]

@@EliTheOBDTech thanks for replying and info. I’m gonna check tomorrow

[@jordanalbea6968]

@@EliTheOBDTech I’ve got a leak in that area I can hear, it’s a solid connection at the throttle body. Where does that hose go from the throttle body? Can’t seem to find where it goes

[@MCRinOC]

Hello sir. Thanks for the video. I have an 05 c230 w P0171. Do you do service? Where are you located?

[@EliTheOBDTech]

Hello there, yes I do, but only Friday - Sunday. I'm located in Pomona, CA

[@MCRinOC]

@@EliTheOBDTech okay from your video I looked and found that the very first hose you point to as a potential vacuum leak was disconnected. I think I pulled it apart when changing a light bulb as it connects to a plastic tube right in that location. Do you know what purpose that vacuum hose serves. It connects possibly to the intake manifold just behind the throttle body. I’m hoping not that I connected the hoses the p0171 goes away. If not, I may reach out to you because you are not far from me. Thanks

[@EliTheOBDTech]

@@MCRinOC To be honest, I never really looked into checking the purpose of that hose, sorry. Yea, if you ever need future service or diagnostics, I'll gladly help.

[@MCRinOC]

@@EliTheOBDTech that sounds great. Thank you very much. I reconnected that hose and I was wondering because it’s still throwing the code. I’m hoping that vacuum line connects to something that takes some time to reset w a drive cycle. So I’ll put some miles on the car and see what happens.

[@loganb595]

If there is a vacuum leak would that be causing a significant loss in power?

[@EliTheOBDTech]

Your MPGs will be affected. Depending on how big of vacuum leak you have. The MAF sensor will not be reporting properly, due to unmetered air.

[@eliezernegron333]

Hey eli Is eli . i have 09 altima 2.5 and had a p0335 and i check the ckp and one of the pins was bend the middle one so i change it but im still getting the code wat should i do next . do i havve to relearn the ckp ?

[@EliTheOBDTech]

From my experience, atleast from 2006 and lower, nissan vehicles don't require crank relearn. Not sure if 2007 and up require it. I haven't worked on a Altima from 2007 and up. When I get a chance, I'll look into AllData.

[@EliTheOBDTech]

Check the condition of the harness connector for spread terminal for the middle one.

[@eliezernegron333]

@@EliTheOBDTech thanks eli i will look up on that 2morrow and i w'll keep u to day ....thank u for the advice🙏👍

[@harnas3848]

Is it a crankcase breather hose ? . It doesn't look like one that's why I am asking.

[@EliTheOBDTech]

It's a vacuum hose, but not sure to what component it connects to.

[@harnas3848]

@@EliTheOBDTech when you google m271 engine vacuum hose- a breather hose pops up. Is it the one which is located underneath the air box and to remove the two parts of it including the valve you need to loosen up the compressor? ( The upper hose is fully exposed after removing the inlet manifold ? .

[@EliTheOBDTech]

@@harnas3848 Yes, that is correct, the pcv valve lives in that area

[@EliTheOBDTech]

Underneath the intake manifold and next to the super charger assembly unit.

[@Juljan-nc4cq]

Yesterday I wanted to clean the MAP sensor of my car and I saw that the pipe that connect to the MAP sensor was missing. can you help me with any information? I have a w203 c180k m271

[@llovertheworld]

Hey Eli can I call you on troubleshooting my 2004 Kompressor coupe on a very long on and off P0171 code

[@EliTheOBDTech]

What's your email? We can talk tomorrow.

[@EliTheOBDTech]

If you can, email me your number.

[@OhhBoyItsUrMUM]

Man if you ever fixed it, what was the problem? Because I keep getting the p0171 on and off, I checked for vacuum leaks and couldn’t hear or see any.

[@llovertheworld]

@@OhhBoyItsUrMUMI was able to locate about 2 years ago now a brand new & very last one available in the USA (Exhaust manifold/Cat and the code disappeared for over a year but now it comes & goes as it pleases,lol if i had to guess from all of the time with different mechanic friends its a very small Vacuum leak h whats funny is that it disappears on rainy days so i think a drop of water seals it somewhere and when the ground is dry it would come back for a few days . Weird sh.t but this summer i will some more time to troubleshoot it h keep you posted. Lastly I found a very tiny leak threw the brake vacuum system as well so check your again with a smoke test and indoors with no wind. Goodluck & keep me posted

[@OhhBoyItsUrMUM]

@@llovertheworld well the only crack I could see is on the air intake hose and it’s on the end that brings the air in, and there a little loose on both ends (if that makes any sense) also I notice the air filter box is kinda jumpy is that normal?

[@llovertheworld]

hey Eli I message your reply, did you get it?

[@EliTheOBDTech]

I just checked my email and no message from you. Did you email me at [e-mail] ?

[@JoseRodriguez-vi1hp]

Eli I have a 1989 nissan d21 having some issues. Im in Pomona, please give me your contact information if you are will to check it out for me

[@cm-yv2cc]

Hey man do you mind giving me a call about my 2004 c230k?

[@EliTheOBDTech]

Email me your number [e-mail] When I get a chance I'll call you.

[@Bingster23]

I have an 01 c320...on and off p0171

[@EliTheOBDTech]

Try performing a smoke test, to check for any vacuum leaks.

[@Mark-wx8ku]

Bad practice to put your hand near that belt with running engine😬

[@EliTheOBDTech]

Good point, but as long as you are careful, no harm foul.

[@Mark-wx8ku]

@@EliTheOBDTech think I'd prefer to turn it off then no risk 😁

[@Kman.]

Of course you can't diagnose w/o looking @ a vehicle, but let me ask you this... Any clue what a $500 repair may be if done by a mechanic "on the side" & not thru a brick & mortar shop? I've got s/one wanting to charge me that amount, but won't share what the issue is unless I pay the *$$$* for his diagnostic scan. In o/words, I can pay him for the scan results...he shares what the problem is, & I can choose to have him do the repair, or I could shop around & have s/one else do the job. Not knowing what the problem is, I DO know he's reasonable, & he's good, so that price of a $500 repair I'm sure would be less than any shop, but does knowing that he would charge $500 for the repair give you ANY clue what may be the issue? I've replaced the MAF & the two air filters, but I don't think that has resolved the issue. Both Advance Auto & O'Reilly's scanned & said it was the MAF. The codes (two of them) wer P0174 & P0171, with "Fule system 2/1 lean & mixture is too lean.

[@EliTheOBDTech]

It's hard to say, but since it's affecting both banks, it looks like you have some sort of vacuum leak. It can be your intake manifold gaskets or most notorious problem for these engines is the intake runner system going bad and creating a vacuum leak.

[@Kman.]

@@EliTheOBDTech Does his labor charge of $500 tip you off to one being more likely than the other? Thx!

[@EliTheOBDTech]

@@Kman. To do either job, the intake plenum must come off.

[@llovertheworld]

I just emailed you my cell#

[@EliTheOBDTech]

Ok, where do you reside?

[@nachotheclaygod]

Hello! if my car has a vacuum leak and is surging at idle, is there a specific hose I should check? i plan on checking all the ones you mentioned but I wanted to see if you had any idea. I also get an MAF code along with all the problems

[@EliTheOBDTech]

I would start with the two small skinny vacuum hoses around the throttle body. Ideally, a smoke test would be the best option.

[@oppongkyekyeku5129]

Wow...what an intuitive video. Thanks a lot Eli

[@Juljan-nc4cq]

Yesterday I wanted to clean the MAP sensor of my car and I saw that the pipe that connect to the MAP sensor was missing. can you help me with any information? I have a w203 c180k m271

[@EliTheOBDTech]

From my understanding, on these models the map/altitude sensor doesn't require a vacuum hose. Is your sensor located near the throttle body?

[@Juljan-nc4cq]

@@EliTheOBDTech yes, dont know how can i send you a photo of my map sensor

[@EliTheOBDTech]

@@Juljan-nc4cq send to my email [e-mail]

[@Juljan-nc4cq]

@@EliTheOBDTech yes, but how can the map sensor work without a conection to measure the pression that gives the boos to the car ?

[@EliTheOBDTech]

@@Juljan-nc4cq It's actually considered an altitude sensor that detects the outside air density and compares to the intake air manifold by using maf sensor data to calculate the manifold absolute pressure.

[@oppongkyekyeku5129]

Wow...what an intuitive video. Thanks a lot Eli