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Thread: crank sensor not learned - changed to "not reported". question

  1. #1
    Potential Tuner
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    May 2019
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    crank sensor not learned - changed to "not reported". question

    I have a 2017 viper. It continues to throw a crank sensor not learned P0315 at least 1-2 times out of 10 upon start up. If it starts up ok and no code, the light will not come on while driving. It only does it at start up. The car is a head cam car. The builder tried a new sensor. No difference. I then had the dealer relearn. It still does it. I just use my OBD connector to reset the codes, and light goes off until next time. Car runs fine otherwise.

    In my tune, it has P0315 as report on 1st error but no box checked. Will it be a problem if I just set it to "not reported" or would no MIL light be a better option but the code will still show in the scanner? I did some searching but I want to make sure by setting it to "not reporting", it won't effect how the car runs. It just won't show the code in the scanner and light will stop coming on.

    Thanks,

    Michael
    Last edited by MSM69Z28; 03-25-2020 at 05:05 PM.

  2. #2
    Senior Tuner 10_SS's Avatar
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    Mar 2012
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    I wonder if it has something to do with low cranking voltage. 2010+ Gen 4 LS3 Camaro's have a similar problem with the crank sensor diagnostic failing during crank (creating a Crank Sensor Fail code), usually only when warm, also people notice it cranks slow. This ended up being due to the crimps on the batt+ wire under hood, and ground wires from block to frame under hood, when they get warm from engine heat, they drop a lot more voltage. Simple solution is to add another engine to chassis ground or bypass the under hood Pos+ batt junction.

    Clearing the code makes the problem go away, but if it is low voltage again on next start, same thing will happen, somewhat randomly. Never a problem on cold start but it also cranks faster on cold start.

    Some people change batteries and starters only to find the problem comes back in 1-2 weeks or months, I personally added a bypass around the batt+ junction under hood, problem solved for 1yr and running. All of the people that have done this report success as well.

    Worth a shot, even if temporary.
    Last edited by 10_SS; 03-26-2020 at 11:08 AM.
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