1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

P0172 Mass Air Flow CEL, high altitude driving

Discussion in '1st Gen. Tacomas (1995-2004)' started by Wulf, Aug 20, 2018.

  1. Aug 20, 2018 at 12:56 PM
    #1
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    While wheeling yesterday I popped a CEL which is code P0172 for running rich and the suggested fix is replacing the MAF. I was also at about 11000 feet when the CEL came on.

    Is it likely that the MAF is actually going bad?
     
  2. Aug 20, 2018 at 6:21 PM
    #2
    Glamisman

    Glamisman Well-Known Member

    Joined:
    Oct 22, 2016
    Member:
    #200436
    Messages:
    4,083
    Gender:
    Male
    there has to be a barometric pressure sensor in the system somewhere but I cant find evan a reference to it in any of the manuals I have... it just might be built into the MAF sensor.
     
  3. Aug 20, 2018 at 6:25 PM
    #3
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,
    I’ve been over eisenhower tunnel 11,000 feet plenty of times and never had a code popped, just reset it and see if it does it again at your elevation 5500
     
  4. Aug 20, 2018 at 6:35 PM
    #4
    whatstcp

    whatstcp currently drunk so don't listen to me

    Joined:
    Aug 3, 2018
    Member:
    #261584
    Messages:
    11,591
    Gender:
    Male
    First Name:
    Ed
    Fontana, CA
    Vehicle:
    2006 Tacoma Regular Cab 2.7l 4x4
    King + Archive Relocation Wheeler's bumps +hydros
    Don't forget that oxygen sensors when failing can influence fuel air mixtures as well. If they have never been replaced or have around 60k then that should be next on your list

    Edit: you can try to save the MAF by buying some MAF cleaner at your local vatozone/walmart as well. 6 bucks and 10 minutes of your time (8 minutes of drying to make sure it's really dry)
     
    Last edited: Aug 20, 2018
    1997tacomav6 likes this.
  5. Aug 20, 2018 at 6:42 PM
    #5
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    I did one of them about 20k miles ago with a Denso replacement.
     
  6. Aug 20, 2018 at 6:44 PM
    #6
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    Ah, I've done that as well without issue. I figured lugging along in 1st fear and 4low might have played into it but it sounds like I should just replace the MAF. I need to get my emissions done this week and get to the DMV before the end of the month
     
  7. Aug 20, 2018 at 6:44 PM
    #7
    whatstcp

    whatstcp currently drunk so don't listen to me

    Joined:
    Aug 3, 2018
    Member:
    #261584
    Messages:
    11,591
    Gender:
    Male
    First Name:
    Ed
    Fontana, CA
    Vehicle:
    2006 Tacoma Regular Cab 2.7l 4x4
    King + Archive Relocation Wheeler's bumps +hydros
    Well shoot maybe it is the maf
     
  8. Aug 20, 2018 at 7:17 PM
    #8
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,
    Haha yup my emissions is due too this month
     
  9. Aug 20, 2018 at 7:19 PM
    #9
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,
    Just try cleaning it with MAF cleaner
     
  10. Aug 21, 2018 at 10:57 AM
    #10
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    I cleaned the MAF and reset the ECU this morning. Truck seems to drive fine, maybe a little more sluggish than usual but it's also pretty cool outside right now. I know you're supposed to put 200~ mi on the ECU to relearn it but I don't think I'll be able to swing that before having my emissions done.
     
    1997tacomav6 likes this.
  11. Aug 21, 2018 at 4:07 PM
    #11
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,
    Got mine done today, the Lincoln and Parker road station was no waiting time at 3pm,
    Easily Passed with flying color.
    In and out in 15 minutes
    FCE555C5-8813-4086-9DAD-DE29B4096356.jpg
     
  12. Aug 21, 2018 at 4:17 PM
    #12
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    Sweet, that's where I was planning on getting mine done :)

    I was gonna do a run on 470 down to Parker road to get the truck nice and warm before I do the test.
     
    1997tacomav6[QUOTED] likes this.
  13. Aug 21, 2018 at 5:17 PM
    #13
    Petrol

    Petrol Well-Known Member

    Joined:
    Apr 24, 2013
    Member:
    #102781
    Messages:
    348
    Gender:
    Male
    Central Va.
    Vehicle:
    Tacoma
    And just FYI, the Mass Air Flow [MAF] sensor is nothing more than a wire or a grid that has current flowing through it. The air flowing across it, cools it and that cooling changes the electrical resistance of the wire or grid. That change in electrical resistance is measured and corresponds to the amount of air flowing across the sensor. That calculation is corrected for the ambient temperature of that air.
    Higher altitudes result in lower air density and generally lower air temperatures BUT because the air is less dense the actual amount of air (the mass of the air) flowing over the sensor is less - so that part is actually self-correcting! It still reads the Mass Air Flow accurately. (it's pretty simple engineering and a pretty cool solution). It's the temperature change that messes with the computer's calculations a bit.

    The computer has algorithms to automatically adjust for altitude changes and the effects of lower atmospheric pressure. The computer reads other values like O2 sensors, throttle position sensors, engine temp, engine speed and it adjusts timing and fuel delivery to meet those conditions. However, every now and then when temperature and atmospheric pressures change rapidly, the computer can get a little outside of its "comfort zone" and throw a code. That code might show a bad sensor but the sensor isn't really bad, the computer just momentarily thinks it is.

    If it throws the code repeatedly then, yes, you may have a bad sensor. If it only does it under rapidly changing conditions occasionally, it's probably just the computer getting confused.
     
  14. Aug 21, 2018 at 5:56 PM
    #14
    jbrandt

    jbrandt Made you look

    Joined:
    Feb 12, 2011
    Member:
    #51038
    Messages:
    17,612
    Gender:
    Male
    First Name:
    Justin
    El Dorado, CA (NOT El Dorado Hills)
    Vehicle:
    '04 TRD Tacoma 4x4 DC
    Kings, J59's Total Chaos UCAs Custom skids Sticker mod
    This happened to me a while back when I was in Colorado on vacation. Back before I had my own code reader. Now, I don't know exactly what code it was, but this sounds like it could be the same. I took it to a shop and they cleared it and said to keep driving. If it comes back on, it could be something else, but since I live a sea level, that was likely the issue.
     
  15. Aug 21, 2018 at 6:16 PM
    #15
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    The truck still seems to be moving along alright, but I did notice that the idle is rough at stop lights.

    I've recently done plugs and wires too, so maybe the MAF is on its way out.
     
  16. Aug 21, 2018 at 6:43 PM
    #16
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,
    You have the bullet I believe, I think Napa or o’Reillys Has the complete unit for 125.00 or so if I remember. I did the Volvo swap but it’s iffy for your year, I might have my old one some where
     
  17. Aug 21, 2018 at 7:26 PM
    #17
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    Iirc I can test mine with a multimeter. I remember people having issues on the 95-96 ECU with the Volvo MAF otherwise it would be a nice upgrade
     
    1997tacomav6[QUOTED] likes this.
  18. Aug 23, 2018 at 8:55 AM
    #18
    Wulf

    Wulf [OP] no brain just damage

    Joined:
    Jan 30, 2015
    Member:
    #147523
    Messages:
    58,513
    Gender:
    Female
    First Name:
    Kira
    1789 28th St, Boulder, CO 80301
    Vehicle:
    rock raisin
    IMG_20180823_093802.jpg
     
    1997tacomav6[QUOTED] likes this.
  19. Sep 23, 2018 at 6:36 PM
    #19
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,
    I have had no issues with both setups, now I have the Volvo setup
     
  20. Sep 23, 2018 at 6:43 PM
    #20
    1997tacomav6

    1997tacomav6 V6 5sp,RegCab,TRD Supercharger,Haltech,meth, 750k

    Joined:
    Oct 5, 2013
    Member:
    #113940
    Messages:
    10,235
    Gender:
    Male
    First Name:
    John
    Denver
    Vehicle:
    97 reg cab, v6 5sp 300hp supercharged, Methonal Injection, 750,001 plus miles, Original Owner
    V6 5sp,RegCab,TRD Supercharger, 1.9” pulley, methanol injected Haltech ECU, AC TRD supercharger,(MUST DO) TRD supercharger ported, every 125,000- 150,000 needs rebuild Projector headlights HID 5 speed manual Amsoil for all drive train Smaller 2” pulley, (MUST DO) 2004 DESNO fuel injectors, zero ping ping, 2004 side door mirrors Dick Cepek Rims, Michelin tires LTX, ( that last 100,000 miles) Now running Dynopro ATM mud and snow tires KN cold air intake Cat back exhaust with ss exhaust tip, Raised exhaust tail pipe to 2" below body line Optima*dry cell battery,red top Alpine sirius radio, 200 watt amp, focal is165 split door pod speakers Focal door speakers Subwoffer behind seat Viper alarm, Electric Locks Dark tinted windows, bucket seats corbeau lg1 Tacoma Rubber floor mats TRD fender extenders, Bilstien shocks, King shocks nerf bars, add a leaf for rear springs trailer iv hitch, electric brake control, Drilled slotted brakes, High carbon steel (MUST DO) EBS green stuff 7000 series pads(MUST DO) TRD engine oil cap TRD stick shift, Marlin crawl shift kit. Rear sliding window 2002 4Runner functional hood scoop cut into Tacoma hood, 4Runner dual overhead map light Gentex Auto dim + Compass + Temp, garage,rearview mirror Snow Methonal kit stage 2 Custom 3 core aluminum radiator Linex bed liner Haltech stand alone ECU, Intake supercharger gauge. Stainless steel brake lines, Custom leather wrapped steering wheel,

Products Discussed in

To Top