Notices
Mercedes Tech Talk Discuss general technical questions and issues about your Mercedes-Benz. Moderated by a certified MB Tech.
Sponsored by:
Sponsored by:

Check Engine Light: Trouble P0101 code?

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Nov 14, 2005 | 03:42 PM
  #1  
NeOmOrTaL's Avatar
Thread Starter
Newbie
 
Joined: Oct 2005
Posts: 18
Likes: 0
Check Engine Light: Trouble P0101 code?

Has anyone of you guys ever had the OBDII P-code: P0101 when your CHECK ENGINE LiGhT came on? My light first came on after I ran out of gas in the middle of nowhere but I don't know if it relates to this problem. After getting it checked by AutoZone, they pulled up this TroubleShoot code: P0101 using their OBDII reader.

Here is what the code mean but I still have no clue on what needs to be fixed :

CODE P0101: " The PCM has determined that there is a discrepancy between the "actual" mass air flow input and the "calculated" mass air flow input derived from the input gathered from other sensors ie. throttle position sensor, barometric pressure sensor ect. "

Any help would be greatly appreciated... Thanks!
Reply
Old Nov 14, 2005 | 07:09 PM
  #2  
rallyeslide's Avatar
Newbie
 
Joined: Oct 2005
Posts: 11
Likes: 0
From: NC/MA
Your engine has a sensor that is placed in the intake tubing that determines how much air is entering the engine.
The TPS [Throttle Position Sensor] tells the ecu the angle of the throttle plate, as well as how fast it is opening [if it is].
The barometric pressure sensor [MAP/Manifold Absolute Pressure] tells the ecu the actual air pressure inside the intake manifold.

Apparently the air flow sensor isn't telling the ecu the same thing the others are, ie the tps and map sensor are saying the engine is at full throttle, sucking in all kinds of air, and the air flow sensor is telling the ecu you're just idling along.
Or vice versa.

Could be a bad air flow sensor.
Could just be a dirty sensor, depending on what kind is in your car [I'm not too familiar with MB yet...]
Could be a bad connection.
Reply
Old Nov 14, 2005 | 11:09 PM
  #3  
NeOmOrTaL's Avatar
Thread Starter
Newbie
 
Joined: Oct 2005
Posts: 18
Likes: 0
Originally Posted by rallyeslide
Your engine has a sensor that is placed in the intake tubing that determines how much air is entering the engine.
The TPS [Throttle Position Sensor] tells the ecu the angle of the throttle plate, as well as how fast it is opening [if it is].
The barometric pressure sensor [MAP/Manifold Absolute Pressure] tells the ecu the actual air pressure inside the intake manifold.

Apparently the air flow sensor isn't telling the ecu the same thing the others are, ie the tps and map sensor are saying the engine is at full throttle, sucking in all kinds of air, and the air flow sensor is telling the ecu you're just idling along.
Or vice versa.

Could be a bad air flow sensor.
Could just be a dirty sensor, depending on what kind is in your car [I'm not too familiar with MB yet...]
Could be a bad connection.
Thanks rallyeslide. Thats alot easier to understand than the explaination they gave me. Your response is similar to what another member told me.... bad MAP sensor. If the sensor is dirty, is there a way to clean it or do I have to replace the sensor? Replacing it seems kind of expensive since I am a college student on a budget.

Anyone else had this problem and was the MAP sensor the problem? Any input would be greatly appreciated...
Reply
Old Nov 14, 2005 | 11:37 PM
  #4  
rallyeslide's Avatar
Newbie
 
Joined: Oct 2005
Posts: 11
Likes: 0
From: NC/MA
It probably would be the air flow sensor and not the map sensor.
To clean it, pick up some electrical connector cleaner from an autoparts store, and CAREFULLY spray inside the sensor [after removing it from the car].
You might want to double check this with someone who knows MBs specifically, as I'm not sure exactly which type MB uses. Some of them can be rather delicate under certain conditions.

If no one else helps, post a pic up of the inside of the sensor and I let you know what to do exactly. As far as cleaning it and whatnot.
Reply
Old Nov 14, 2005 | 11:56 PM
  #5  
shorthair's Avatar
Senior Member
 
Joined: Sep 2004
Posts: 404
Likes: 1
From: Albany, NY
2014 C300, sport, black/black
There are a whole lot of existing posts about this error code and how to fix it, where to order it from at cheaper than dealer pricing, and the various methods of cleaning that people tried, which mostly don't fix the problem and you end up replacing the part anyway.
Reply
Old Nov 15, 2005 | 03:58 PM
  #6  
NeOmOrTaL's Avatar
Thread Starter
Newbie
 
Joined: Oct 2005
Posts: 18
Likes: 0
Originally Posted by rallyeslide
It probably would be the air flow sensor and not the map sensor.
To clean it, pick up some electrical connector cleaner from an autoparts store, and CAREFULLY spray inside the sensor [after removing it from the car].
You might want to double check this with someone who knows MBs specifically, as I'm not sure exactly which type MB uses. Some of them can be rather delicate under certain conditions.

If no one else helps, post a pic up of the inside of the sensor and I let you know what to do exactly. As far as cleaning it and whatnot.
From my understanding, I will try to remove both the air flow sensor and the MAF sensor to clean it. I have search other threads and it seems to be the MAF sensor... so I am probably going to try that first.

Thanks to everyone who has help me with this issue. Its nice to know friendly tech support is only a few clicks away.
Reply
Old Nov 15, 2005 | 04:03 PM
  #7  
NeOmOrTaL's Avatar
Thread Starter
Newbie
 
Joined: Oct 2005
Posts: 18
Likes: 0
Originally Posted by shorthair
There are a whole lot of existing posts about this error code and how to fix it, where to order it from at cheaper than dealer pricing, and the various methods of cleaning that people tried, which mostly don't fix the problem and you end up replacing the part anyway.

Thanks shorthair for your help. I have searched the board and it seems like cleaning it seems to be first thing I should do instead of going to the dealership only for them to tell me to replace it when it just needs cleaning.

Btw guys, I am at 90K miles but its an 02 C230. At this high of a mileage, is it normal to replace it or is it still worthy of cleaning it only to have it go bad again?
Reply
Old Nov 15, 2005 | 05:04 PM
  #8  
Air Marshall Eldritch's Avatar
MBWorld Fanatic!
 
Joined: Feb 2002
Posts: 9,815
Likes: 13
John Deere
I know a guy that sells new ones for around $161 if you need it. Beats the dealer price by a fair bit.
Reply
MB World Stories

The Best of Mercedes & AMG

story-0

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-1

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-2

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-3

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-4

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-5

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-6

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-7

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-8

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
story-9

10 Most Reliable Mercedes-Benz Models You Can Buy Used

 Verdad Gallardo
Old Nov 15, 2005 | 08:57 PM
  #9  
rallyeslide's Avatar
Newbie
 
Joined: Oct 2005
Posts: 11
Likes: 0
From: NC/MA
Originally Posted by NeOmOrTaL
From my understanding, I will try to remove both the air flow sensor and the MAF sensor to clean it. I have search other threads and it seems to be the MAF sensor... so I am probably going to try that first.

Thanks to everyone who has help me with this issue. Its nice to know friendly tech support is only a few clicks away.

The MAF sensor IS the air flow sensor. MAF = Mass Air Flow

Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 05:34 AM.

story-0
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-1
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-2
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-3
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-4
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-5
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-6
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-7
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-8
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE