I got a code P0171
Thread Starter
Newbie
Joined: Jul 2018
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C230
I got a code P0171
I got a Code P0171 this monday.
I try to replace spark plug first,maybe clean the MAF.
Car drive well but I feel idle more lower.
Does any advice to check or change first?
Thank you.
I try to replace spark plug first,maybe clean the MAF.
Car drive well but I feel idle more lower.
Does any advice to check or change first?
Thank you.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,265
Likes: 169
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
P0171 too lean. Means potential vaccum leak, ie bad hoses, ad or
as the man says, O2 sensors, MAF etc.
1st look for bad or leaking hoses, and clean the MAF see how that goes.
If you're not up to date on your maint. well it could be anything.
Read the codes with a Mercedes specific unit, you may get more info.
as the man says, O2 sensors, MAF etc.
1st look for bad or leaking hoses, and clean the MAF see how that goes.
If you're not up to date on your maint. well it could be anything.
Read the codes with a Mercedes specific unit, you may get more info.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,265
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From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Oh...thats not good.
I'm not the M271 expert here. Hope others will chime in.
Early M271 had lots of problems supposedly fixed by new head design in 2005.
Still though, single row chain can stretch and cause all kinds of weird timing problems.
Have you kept up on standard maint? How many miles do you have?
I'm not the M271 expert here. Hope others will chime in.
Early M271 had lots of problems supposedly fixed by new head design in 2005.
Still though, single row chain can stretch and cause all kinds of weird timing problems.
Have you kept up on standard maint? How many miles do you have?
Thread Starter
Newbie
Joined: Jul 2018
Posts: 8
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C230
Oh...thats not good.
I'm not the M271 expert here. Hope others will chime in.
Early M271 had lots of problems supposedly fixed by new head design in 2005.
Still though, single row chain can stretch and cause all kinds of weird timing problems.
Have you kept up on standard maint? How many miles do you have?
I'm not the M271 expert here. Hope others will chime in.
Early M271 had lots of problems supposedly fixed by new head design in 2005.
Still though, single row chain can stretch and cause all kinds of weird timing problems.
Have you kept up on standard maint? How many miles do you have?
142000 Mile.
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Super Member
Joined: Sep 2016
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From: New England! :-)
2005 C230K Sport Coupe
Originally Posted by kennylaim
I just bought this car three month ago.
142000 Mile.
142000 Mile.
Fwiw, You're playing Russian Roulette with that POS timing chain.
If that timing chain breaks, then the whole engine worthless.
The M271 has one/few vacuum hoses that get holes/tears from heat and rubbing.
The good thing - the replacement hoses are cheap and easy to get.
The bad thing - it takes a few hours to get to and to replace the hoses.
A smoke leak test may be able to show a leak from that area/hose(s). Or, maybe not. It could be a small leak, and the smoke could get "lost/dispersed" before it can be seen.
Do a search on M271 hose vacuum leak.
https://www.google.com/search?q=m271+hose+vacuum+leak
Fwiw, I suggest replacing the M271 timing chain every 80K miles.
I have degrees, teaching, and industry experience in mechanical engineering and failure rates/reasons. So, my views may differ from other people.
Also, update your user profile to show car year, car model, and area in the world.
Good Luck!
Last edited by RedGray; Sep 7, 2018 at 11:41 PM.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,265
Likes: 169
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Just google "$12 Hose C230". Lots of stuff...
my engine is different so no 1st hand knowledge.
Mercedes will replace the one hose for free, but any vacuum leaks will cause this.
And or O2 sensors, or MAF. I kept getting P0171 a couple years ago,
till finally read with actual SDS and it said straight up the MAF was shorted.
Of course this was AFTER I'd checked everything else, and I did end up replacing some split hoses,
and put in new O2 sensors since they were 'lazy' when I checked them in Torque graph and were like over 100K miles old and you're supposed to change them every 100K.
my engine is different so no 1st hand knowledge.
Mercedes will replace the one hose for free, but any vacuum leaks will cause this.
And or O2 sensors, or MAF. I kept getting P0171 a couple years ago,
till finally read with actual SDS and it said straight up the MAF was shorted.
Of course this was AFTER I'd checked everything else, and I did end up replacing some split hoses,
and put in new O2 sensors since they were 'lazy' when I checked them in Torque graph and were like over 100K miles old and you're supposed to change them every 100K.
Last edited by C230 Sport Coup; Sep 11, 2018 at 03:55 PM.
Newbie
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C230K
I had the same code pop up p0171 pnd mod1 and p0171 cnf mod1 1 both said bank1 system to lean. How ever the code came off a couple of days later. How serious is it if the check engine light turns off on own?
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C230K
