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P0101 Trouble Code/Engine Code

Discussion in 'General Tundra Discussion' started by csuviper, Jan 24, 2015.

  1. Jan 24, 2015 at 10:22 PM
    #1
    csuviper

    csuviper [OP] Moderator Staff Member

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    Some Mods :) See build thread for details
    I decided to add a new thread for this topic to discuss my specific incident , investigation and research in an effort to get a resolve and help others that experience the same trouble code.

    P0101 - Mass or Volume Air Flow Circuit Range/Performance Problem
    Here is a link to the trouble code: http://engine-codes.com/p0101.html

    The Trouble code first occurred when driving down the highway a few days after installing my new exhaust. The code popped up on my UltraGauge and the check engine light turned on. To back up a little bit and eliminate some possibilities here is a schedule of related items:

    1. Hypertech Speedo Calibrator install - 4/17/14
    2. Hypertech Interceptor install- 6/12/14
    3. Drop-in AFE Pro Dry Air Filter install - 7/13/14
    4. BA Mufflers 6" Catback Exhaust install - 12/29/14

    I did not see this code after the HI was installed.
    I did not see this code after the drop in filter was added.
    I only saw the code after the exhaust was installed.

    When I added the drop in filter in July, I called Hypertech because there wasn't an option for drop in filter for the update to the software. They told me to run the stock setting. No problems till I added the exhaust. Guessing that it opened up air flow just enough to throw the sensors off.

    I emailed the BA Muffler guys and they said that code is very common for Tundras. Happens to his truck with very large tires and goes away with smaller tires installed. Shouldn't be related to exhaust. They made this exhaust specifically for the tundra and have much experience with it.

    I did some testing to try to figure out what the problem was. I cleared the code and didn't have the code for several days. Didn't get on the highway so that was the first clue.
    I hit the highway and received the code when I got to ~75mph (co highway speed limit). Cleared the code again and got the code again ~75mph. Clue #2.
    Some discussions on the forum led me to look at the Hypertech Interceptor as a possible cause. I then decided to unplug the HTI and drive 75mph. No code. Found the cause.
    Now i need to find the resolve.

    [​IMG]

    https://vimeo.com/116206020

    Update 1/26/15:
    Ok I added the stock paper filter in and plugged in the HTI in tonight. I hit the highway and 75-80 mph, no code!! I played around a little bit, purely official professional scientific experimentation. Went an undisclosed speed and let off the gas, bam, code again. Bummer. I was feeling confident that I was good with the paper filter like TruckyTruck mentioned. No check engine light this time, only saw the code on the UltraGauge. My guess right now is that the reading on the MAF is out of spec for a millisecond. Enough for the Ultagauge to pick up on it but not long enough for the truck to call for a check engine light.

    Update 2/18/15:
    Got the code again today going up a steepish hill on the highway. Stock air filter. No CEL, just UltraGauge. Cleared the code and did the same hill in the evening and no code.

    Update 5/19/15:
    I went on a trip to Kansas over easter weekend in April ~444 miles each way straight east on I70. Had the cruise set at 83mph to stay under 10 over to avoid a ticket.

    No codes on the ultraguage and no CEL with hypertech and paper filter installed. . Haven't had a code since. I have since put the Drop-in AFE Pro Dry Air Filter back in and no codes yet with that either.
    I'm kinda thinking that the exhaust opened up the back pressure a little and it took a while for the computer to adjust for it.
     
    Last edited: May 19, 2015
  2. Jan 25, 2015 at 11:47 AM
    #2
    Sean266

    Sean266 #ThinBlueLine Staff Member

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    I'm surprised they don't have a software update for this.
     
  3. Jan 25, 2015 at 10:29 PM
    #3
    14burrito

    14burrito New Member

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    And this is what everyone with an HTI deals with and this is why more people don't buy one...known issue with no fix.

    Some people try an aftermarket CAI tune with success some still throw the code.

    Most people throw the code while towing in the hills.....which is why most people buy, for the towing performance aspect.
     
  4. Jan 26, 2015 at 7:33 AM
    #4
    csuviper

    csuviper [OP] Moderator Staff Member

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    I have read some other forums on this with people going back and forth without really coming up with a good solution. Hypertech replaced the unit for some. Some it fixed the problem. Some it didn't.

    My plan is to contact Hypertech to see if they now have a solution after all of the other feedback from users. I am hoping they do. If not i will see if i can push them for a software update. If this doesn't work then i will be testing different tunes for the CAI to see which one works the best and doesn't throw the code. The problem i have is that i am not willing to throw money at dynos and i cannot see the details of the air fuel ratio or other specs that are changed with the HTI.
     
  5. Jan 26, 2015 at 8:50 PM
    #5
    TruckyTruck

    TruckyTruck New Member

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    Man... Hope you find a solution. :confused:

    I'd really like to hear what happens with the paper filter.
     
  6. Jan 26, 2015 at 9:12 PM
    #6
    JROCK915

    JROCK915 Trust noone, and be prepared!

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    2011 Trail ready SR5
    Icon 1.5" leaf pack, w/ Pro Comp 1" block Rear Pro Comp SS shocks ToyTec/Eibach coil overs, on Pro Comp SS shocks, SPC UCA AFE Stage II C.A.I, and throttle body spacer N-Fab nerf bars N-Fab RSP front bumper with Hella Optilux 30" LED bar, and Hella Optilux 4" (2) HID driving lights Federal Couragia 33x12.5x20, wrapped around 20x9 Fuel Boost Fender flares Spyder LED tail lights (smoked out)
    Thanks for the 411. I have the AFE C.A.I stage II. Was thinking of adding the HTI. May break the bank & go with the Bullydog. Unless HT fixes the issues.
     
  7. Jan 26, 2015 at 9:31 PM
    #7
    csuviper

    csuviper [OP] Moderator Staff Member

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    Ok I added the stock paper filter in and plugged in the HTI in tonight. I hit the highway and 75-80 mph, no code!! I played around a little bit, purely official professional scientific experimentation. Went an undisclosed speed and let off the gas, bam, code again. Bummer. I was feeling confident that I was good with the paper filter like TruckyTruck mentioned. No check engine light this time, only saw the code on the UltraGauge. My guess right now is that the reading on the MAF is out of spec for a millisecond. Enough for the Ultagauge to pick up on it but not long enough for the truck to call for a check engine light.
     
    JROCK915 likes this.
  8. Jan 27, 2015 at 9:36 PM
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    TruckyTruck

    TruckyTruck New Member

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    I wonder how many guys are getting that code and don't realize it.
     
  9. Feb 11, 2015 at 9:05 PM
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    Mike

    Mike Tread lightly.

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    yep bank account is running low from it..
    Sounds like to me maf is dropping out doesnt sound out of spec... if it was out of spec your cel would stay on..

    Does anyone have a wiring diagram of the ecm and it components in question.. I have a theory on this..
     
    Last edited: Feb 11, 2015
  10. Feb 15, 2015 at 11:27 PM
    #10
    csuviper

    csuviper [OP] Moderator Staff Member

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    Hmm don't have the wiring diagram. Interested in your theory though.
     
  11. Feb 17, 2015 at 3:34 PM
    #11
    Mike

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    theory is base on the maf itself... I have feeling the maf is either

    (A) not ground correctly
    (B) wiring is going to and from the maf is passing coils screwing up the signal ( likely wiring is not shielded)
    (c) not enough ground points on the system.. too much ground on one line causing engine noise too..

    there are more.. these are more important than rest.
     
  12. Feb 17, 2015 at 11:35 PM
    #12
    csuviper

    csuviper [OP] Moderator Staff Member

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    Got the code again today going up a steepish hill on the highway. Stock air filter. No CEL, just UltraGauge. Cleared the code and did the same hill in the evening and no code.
     
  13. Feb 18, 2015 at 5:23 AM
    #13
    Virgils12

    Virgils12 New Member

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    Csu do you think it's possible your grill is not letting enough air flow into the engine compartment? And thus messing with the maf sensor?
     
  14. Feb 18, 2015 at 5:31 AM
    #14
    Sean266

    Sean266 #ThinBlueLine Staff Member

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    That is so strange...
     
  15. Feb 18, 2015 at 7:19 AM
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    Mike

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    has the recall been done yet on the ecm yet?
     
  16. Feb 18, 2015 at 9:00 PM
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    TruckyTruck

    TruckyTruck New Member

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    Exhaust?
     
  17. Feb 18, 2015 at 9:08 PM
    #17
    TruckyTruck

    TruckyTruck New Member

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    Your truck didn't pop that code until after you installed the exhaust did it? Your ultra gauge shows the code but no check engine light, right?
     
  18. Feb 18, 2015 at 9:32 PM
    #18
    csuviper

    csuviper [OP] Moderator Staff Member

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    Correct
     
  19. Feb 19, 2015 at 9:29 AM
    #19
    Sean266

    Sean266 #ThinBlueLine Staff Member

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    I think it's the exhaust as U mentioned it's fairly common?
     
  20. Feb 19, 2015 at 3:33 PM
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    TruckyTruck

    TruckyTruck New Member

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    Well I wonder how many of us would see that code if we hooked up the ultra gauge. I've got one but never thought about using it since I don't get the check engine light. I'll hook it up next week and see what mine says. I don't think there is anything wrong with the exhaust, but rather how sensitive these trucks are. Or something like Mike mentioned earlier.
     
  21. Feb 19, 2015 at 4:15 PM
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    Mike

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    csuviper... question on your exhaust here...... Did the diameter of the pipes change when you went to the new exhaust. say it was 3 and it went to three half inch diameter?
     
  22. Feb 19, 2015 at 7:48 PM
    #22
    TruckyTruck

    TruckyTruck New Member

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    Mike, just from research before and after I bought mine from the same company, the exhaust pipe size is the same. But his mufflers are a straight thru design now vs the stock chambered muffler.
     
  23. Feb 20, 2015 at 8:10 AM
    #23
    csuviper

    csuviper [OP] Moderator Staff Member

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    Correct here. Same size pipe, utilizes stock single pipe on the exit.
     
  24. Feb 20, 2015 at 9:04 AM
    #24
    Mike

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    I see the problem now... toyota tuned the ecm to that exhaust they used... They tuned it via 02 sensors not uncommon..

    You freed up the exhaust in flow therefor you changed the temp on the 02 sensors... The temp of the O2 sensors are not matching whats programmed into the Ecm memory bank or curve for a set engine temp under normal operation.... Toyota is using the O2 as a meter just like it maf... Those two must match the curve in place... Now With the exhaust free flowed O2 temps went down, the ecm has no choice but to flag in maf for error. Its the only thing. Ecm cant flag the 02 because there is nothing wrong with it.. What it sees in a increase flow in air from the MAf not matching O2 sensors there is your error..

    Willing to bet this is the whole problem right here.
     
  25. Feb 20, 2015 at 12:09 PM
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    csuviper

    csuviper [OP] Moderator Staff Member

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    Crazy. Good analysis. That could be it.
    Thing is why is it only seen with the Hypertech installed? I might have to do some more driving without the Hypertech to see if I can get it to throw the code.
     
  26. Feb 20, 2015 at 12:25 PM
    #26
    Mike

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    Remember...

    since the hypertech is a plug in base system, the hypertech adds stuff (forces the ecm) to do what it wants ( what it the hypertech is programmed to do) ... Ecm has no choice but to take the command and run it even tho its not in range that toyota gave it...

    edit: if your not running the hypertech now, and getting the code the hypertech will only , amplified the bad signal and make it WORSE on the ECM..
     
  27. Feb 20, 2015 at 1:09 PM
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    Sean266

    Sean266 #ThinBlueLine Staff Member

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    My OCD would go crazy with the code, and I would end up just removing the HT...
     
  28. May 19, 2015 at 9:37 AM
    #28
    csuviper

    csuviper [OP] Moderator Staff Member

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    Forgot to update everyone in a while. I went on a trip to Kansas over easter weekend in April ~444 miles each way straight east on I70. Had the cruise set at 83mph to stay under 10 over to avoid a ticket.

    No codes on the ultraguage and no CEL with hypertech and paper filter installed. Haven't had a code since. I have since put the Drop-in AFE Pro Dry Air Filter back in and no codes yet with that either.
    I'm kinda thinking that the exhaust opened up the back pressure a little and it took a while for the computer to adjust for it.
     
    Last edited: May 19, 2015
    14burrito likes this.
  29. May 19, 2015 at 1:32 PM
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    TruckyTruck

    TruckyTruck New Member

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    I'm Really glad to hear that... I love the idea of the reusable filter, but I won't run on in my truck. It dropped my low end tq pretty bad.
     
  30. May 19, 2015 at 3:03 PM
    #30
    csuviper

    csuviper [OP] Moderator Staff Member

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    I don't feel a difference between the two filters at all.
     
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