How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Marcco Your Own Question

Marcco
Marcco, NIASE Auto / Diesel Master Tech
Category: Car
Satisfied Customers: 1
Experience:  35 Yrs - NIASE, J.I. CASE, GM and ATRA Certified Auto, Diesel, Trans and Computer Systems Consultant
Type Your Car Question Here...
Marcco is online now
A new question is answered every 9 seconds

I just bought 06 express van with a Duramax diesel. codes p0299

Customer Question

I just bought 06 express van with a Duramax diesel. codes p0299 turbo underboost, p0087 fuel rail pressure too low, p0101 mass air flow circuit out of range. looking around i found that someone has replaced the turbo and the a tube that ran from valve cover to other was loose. But after tightening everything the code po299 was the newest code that pop up
Submitted: 5 years ago.
Category: Car
Expert:  Marcco replied 5 years ago.

The Mass Air Flow (MAF) senses the amount of air about to enter the engine, the Power Control Module (PCM) uses this data to adjust the fuel supplied to the engine. If the reading is out of range (Low for example) it will cause the domino of events noted by your trouble codes when the fuel pressure is lowered the fuel supplied is lowered and the turbo in turn will not produce as much boost because it depends on exhaust temperature to produce full boost pressures, so the botXXXXX XXXXXne is the MAF code is the relevant issue. the PCM is not receiving the proper signal voltage and is adjusting accordingly. So to diagnose the MAF problem a quality scan tool can read the MAF sensor output in grams per second, at idle fully warmed up it should read approximentaly 4.0 to 9.0 grams per second. When the engine is accelerated the values should rise quickly with engine RPM and remain steady at a steady engine RPM.

First check the voltage supply and ground circuits by disconnecting the connector from the MAF sensor connect the Pos lead of the volt meter to the pink wire and the Neg lead to the Black/White wire. Turn the key "ON" and you should read approx. 12 volts. If there is no voltage, of course check ALL related fuses with a test light or meter first! Then check the ground by moving the Neg meter lead to a known good ground like the batt.

It is also possible that the replacement MAF sensor has a problem, but the scan test mentioned above will verify this. But it is critical to test the power and ground circuits for a complete diagnosis!

 

Good Luck!!!

Customer: replied 5 years ago.
My solus is telling me the mass air flow (gm/sec) 49.00 ?
and mass air plug is 12v

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
< Last | Next >
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
  • used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future. David L. Richmond, TX
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil Marysville, CA
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles Walnut Creek, CA
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue Charleston, WV
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim Castleberry, FL
  • The nearest Volvo dealer is 160 miles away. Best $15 bucks I have spent in a long time! Paul M Corpus Christi, TX
 
 
 

Meet The Experts:

 
 
 
  • Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
< Last | Next >
  • http://ww2.justanswer.com/uploads/MU/muddyford/2012-6-13_1204_1.64x64.png Chris (aka-Moose)'s Avatar

    Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
  • http://ww2.justanswer.com/uploads/TE/TedG/2012-6-15_14759_avaLarge.64x64.jpg Ted G.'s Avatar

    Ted G.

    ASE Certified Technician

    Satisfied Customers:

    1596
    20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
  • http://ww2.justanswer.com/uploads/joecamel90/2008-11-13_03615_head_shot.jpg George H.'s Avatar

    George H.

    ASE Certified Technician

    Satisfied Customers:

    1311
    ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
  • http://ww2.justanswer.com/uploads/AM/amedee/2013-10-24_23656_Amedee1.64x64.jpg Amedee's Avatar

    Amedee

    ASE Master Tech

    Satisfied Customers:

    2367
    ASE Master Tech advanced level specialist
  • http://ww2.justanswer.com/uploads/SU/supermechanic/2013-8-23_03546_500.64x64.jpg Jerry's Avatar

    Jerry

    Master Mechanic

    Satisfied Customers:

    1906
    ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager
  • http://ww2.justanswer.com/uploads/CR/crzydrvr00/2013-11-3_12123_246347.64x64.jpg Richard's Avatar

    Richard

    ASE Certified Technician

    Satisfied Customers:

    942
    12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes
  • http://ww2.justanswer.com/uploads/ST/Steve7654/2012-6-5_215929_japic800x660.64x64.jpg Steve's Avatar

    Steve

    Auto Service Technician

    Satisfied Customers:

    1980
    25+ yrs experience as a professional working technician; ASE L1 master technician