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Thread: 06 LS7 swap, P0315, crank relearn not working

  1. #1
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    06 LS7 swap, P0315, crank relearn not working

    I have a ls7 swapped into an FD rx7 using a modified vette harness and an 06 z06 E38 ECM. I am getting a P0315 code for the crank relearn. I have tried a million times to get the relearn to work unsuccessfully. I have searched the forum and read numerous suggestions on how to get it to work and I have tried everything people have suggested and it will not run.

    I have brake input from my brake pedal switch, clutch input from my clutch switch, and in the logger i can see with key on they both function properly. When i try to do the learn procedure i get the error that it cannot be done with faults, which i dont have any besides the P0315. I tried disabling the P0315 code and that didnt work.

    I see a lot of threads with similar issues but they never seem to have a proper resolution. I have several drivability issues that may or may not be a result of this issue.

    Any ideas? I read people discussing parking brake input, but I don't see anything on the wiring diagrams or e38 pinouts that indicate parking brake signal is ever sent to the ecm

    06_z06_vats.hpt

  2. #2
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    Why doesn't disabling 315 work? It should.
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    Quote Originally Posted by Alvin View Post
    Why doesn't disabling 315 work? It should.
    I dont know. I tried it and I still get the error that there cannot be any faults even though i have no active DTCs. Im guessing im not meeting some parameters GM wants but it obviously wont tell me what. I added the brake input thinking that was it, but it doesnt work. I am still having an issue with the brake input that i have mentioned in another thread but it has no solution either. My brake signal works key on engine off, but when you start the engine it doesn't work anymore. I

  4. #4
    Tuning Addict blindsquirrel's Avatar
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    Real scan tools give much better feedback about the process and what conditions are not being met. With a Tech2, on some platforms, it'll say 'minimum coolant temp not met', display the current ECT, and have you wait for the next step. Or it will say 'brake not applied'. With HPT you're just blind to what's happening or not happening.

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    Quote Originally Posted by blindsquirrel View Post
    Real scan tools give much better feedback about the process and what conditions are not being met. With a Tech2, on some platforms, it'll say 'minimum coolant temp not met', display the current ECT, and have you wait for the next step. Or it will say 'brake not applied'. With HPT you're just blind to what's happening or not happening.
    So interestingly, i did get both those messages from HPtuners during my numerous attempts over several hours. So i dont think the ect or the brake input are my issue. Im trying to see if i can find someone with a tech2 to attempt it. I hate to just disable the code as i do have some driveability issues.

  6. #6
    Tuning Addict blindsquirrel's Avatar
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    In the P0315 description I notice this:
    Important: The CKP System Variation Learn Procedure may have to be repeated up to 5 times before the procedure is learned.
    Yeah, have fun with that if you're a flat-rate guy in the dealership! Jesus.

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    P0315 will not cause any issues disabled.

    I've seen some mail order tuners turn it off on all tunes just so they don't need to get a CASE relearn when they get the new modules.

    I have to disable it on Hotrod swaps/racecars/boats/airplanes that don't have a brake or emergency brake input. Never a issue.
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    Quote Originally Posted by Alvin View Post
    P0315 will not cause any issues disabled.

    I've seen some mail order tuners turn it off on all tunes just so they don't need to get a CASE relearn when they get the new modules.

    I have to disable it on Hotrod swaps/racecars/boats/airplanes that don't have a brake or emergency brake input. Never a issue.
    I keep reading people discussing parking brake, but the wiring diagram for the corvette doesnt show there is a parking brake input to the ecm. Is there really a parking brake input?

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    so to follow up.... after a ton of searching and reading, i am more confused than ever on the e-brake aspect of it. In fact- i found 2 directly conflicting posts in 2 different threads about it...
    case_ebrake.JPGp0315.JPG

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    Another update- tried a snap on scanner today and gave the same message- cannot perform with faults present

  11. #11
    Tuning Addict blindsquirrel's Avatar
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    I imagine that in GM-speak that means it needs to see certain DTCs run and pass, not just no current DTCs present, and disabling those unspecified DTCs will prevent the relearn routine.

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    I've mentioned several times already. The relearn isn't important. Turn it off and move on.
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  13. #13
    A crank relearn helped with some (and they very well may have been erroneous) misfire issues on a well worn LS2 GTO. The motor had been apart a couple of times and sensors replaced here and there. PCM was not original to it. No internal engine upgrades that I could tell in the short time I owned it. I chased a misfire issue with it and on the advice of a GM tech, tried the relearn and low and behold, no more misfire codes. It felt more responsive to me, but I didn't verify anything beyond the misfire code being gone.

    I am unable to do one on my Ls3 swapped car now. I've tried a Snap On tool as well and exact same results. DTC's present. This car has the random misfire and crank not learned codes as well.

    Ideally, it would say checking XXX, passed, checking XXX passed, checking XXX, Fail. I'm not aware of anything that shows what it is looking for next. My understanding it is necessary and a part of certain procedures. Yes I can disable the codes too, but I'd like to know what it is that's preventing the procedure from progressing.

  14. #14
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    Quote Originally Posted by cpd004 View Post
    A crank relearn helped with some (and they very well may have been erroneous) misfire issues on a well worn LS2 GTO. The motor had been apart a couple of times and sensors replaced here and there. PCM was not original to it. No internal engine upgrades that I could tell in the short time I owned it. I chased a misfire issue with it and on the advice of a GM tech, tried the relearn and low and behold, no more misfire codes. It felt more responsive to me, but I didn't verify anything beyond the misfire code being gone.

    I am unable to do one on my Ls3 swapped car now. I've tried a Snap On tool as well and exact same results. DTC's present. This car has the random misfire and crank not learned codes as well.

    Ideally, it would say checking XXX, passed, checking XXX passed, checking XXX, Fail. I'm not aware of anything that shows what it is looking for next. My understanding it is necessary and a part of certain procedures. Yes I can disable the codes too, but I'd like to know what it is that's preventing the procedure from progressing.

    That's understandable.. The CASE relearn is needed to find misfires. You can also disable the misfire timers.. Something that has to be done with almost all cams anyway.

    But the CASE relearn doesn't effect fueling or timing or anything like that.
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