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Thread: MAP TPS Failed - 2021 E90 Whipple Silverado

  1. #1
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    MAP TPS Failed - 2021 E90 Whipple Silverado

    Need help understanding why this truck keeps setting a "MAP TPS Failed" MAF status. I added a SCIAP to the truck last night and thought it resolved it. Then, the problem came back. Only at WOT at first, then it started doing it above ~40% pedal position again as seen in the attached log.

    The truck is basically stock with a 3.0 Whipple. 2021 6.2 10-speed Silverado, lifted with wheels & tires.

    The attached log has it failing about 3:52. I try to make a WOT pull shortly after that and the truck did a weird jerky downshift that it has never done before.

    The truck occasionally sets a P0121 as well. Even when I set the test thresholds to disable the tests (via write entire as well) it still sets the code. The truck currently has a LT4 throttle body swapped on to it to test temporarily and it makes no difference. It passes a sweep test via Snap On scanner with the stock throttle body. The throttle body extension harness has been removed and inspected as well. I'm assuming the P0121 is tune related and connected to the MAF failing.

    If I keep it under ~35-40% pedal position, there don't seem to be any problems. I'm sure the issue lies in the DD or VT somewhere, but I can't seem to make it stop no matter how I increase/decrease the tables...hoping someone can point me in the right direction. I'll kick some dollars your way to get it resolved ASAP if need be.
    Attached Files Attached Files

  2. #2
    I have had very good luck fixing similar issues.

    The SCIAP addition i have found fixes the P0121 issue right off the bat.
    So hearing that is still present makes me concerned that the sensor is not plumbed correctly. Post throttle, pre-roots
    This also tracks with the MAF going into a TPS failed mode.

    Few notes.
    Re-enable the MAP AAP1/2 Volt tests
    Reset the Max PR fault values back to .9
    Having these disabled can mask potential issues and make them appear differently

    For your setup i would expect a P101 right around the 100kpa mark, and a P2227 error code to appear, but seeing the P0121 makes me think that something else is wrong.
    Last edited by will_974; 1 Week Ago at 12:08 AM.

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    Quote Originally Posted by will_974 View Post
    I have had very good luck fixing similar issues.

    The SCIAP addition i have found fixes the P0121 issue right off the bat.
    So hearing that is still present makes me concerned that the sensor is not plumbed correctly. Post throttle, pre-roots
    This also tracks with the MAF going into a TPS failed mode.

    Few notes.
    Re-enable the MAP AAP1/2 Volt tests
    Reset the Max PR fault values back to .9
    Having these disabled can mask potential issues and make them appear differently

    For your setup i would expect a P101 right around the 100kpa mark, and a P2227 error code to appear, but seeing the P0121 makes me think that something else is wrong.


    Sensor is plumbed correctly and functioning as it should I believe. It's in the port on the driver's side of the blower, behind the throttle body, below the EVAP solenoid.

    I'll try those changes you suggest and see what happens. I've basically been throwing things at the wall to see what changes and nothing really ever does. Other than the MAF status and P0121, the truck feels great to drive.

  4. #4
    Quote Originally Posted by 2000_SS View Post
    Sensor is plumbed correctly and functioning as it should I believe. It's in the port on the driver's side of the blower, behind the throttle body, below the EVAP solenoid.

    I'll try those changes you suggest and see what happens. I've basically been throwing things at the wall to see what changes and nothing really ever does. Other than the MAF status and P0121, the truck feels great to drive.
    On looking at the log, I do agree the SCIAP appears to be plumbed correctly.
    However, taking a diff of your calibration against the base, some things feel off.

    You have MAP Error checks disabled and SD mode code patch applied
    These things make it seem like the attempt to have it running in MAF only mode???
    This is not going to work well when changing to SCIAP because the Volumetric efficiency is still used along side the MAF even if not used for fueling.
    If this is too far off, it could for sure throw a P0121 code.
    I'm a little ignorant to the E90/E99 volumetric fueling mechanism, so that may be false and if so i apologize.

  5. #5
    Senior Tuner Ben Charles's Avatar
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    I have a test for you to try.. leave SCIAP on the map but on the “supercharger mode” click disable opposed to enable and retry

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    Tuning Addict edcmat-l1's Avatar
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    Ben is a smart guy. Might wanna listen.

    Didn't look at anything. Just passing through LOL

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    Quote Originally Posted by Ben Charles View Post
    I have a test for you to try.. leave SCIAP on the map but on the “supercharger mode” click disable opposed to enable and retry
    will do. thanks.

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    Quote Originally Posted by Ben Charles View Post
    I have a test for you to try.. leave SCIAP on the map but on the “supercharger mode” click disable opposed to enable and retry
    went through the tune and I'm not sure I understand what you're referencing. Are you talking about the ECM 215 parameter? Engine>SC/TC General>Forced Induction Type Fitted? It's currently set to "None." I can't find anything else that sounds like "supercharger mode."