The P0315 code means that the crankshaft position needs to be relearned, usually this happens when swapping in a different ECM, it is really simple to do the relearn with a dashhawk, or the dealer can also do it, and it only takes a couple minutes to do.
With the dashhawk here are the instructions for the relearn:
1. Be sure the engine coolant temperature is at LEAST 158 degrees F. The DashHawk will check and will not let
you perform the procedure if this condition is not met.
2. Set the Parking Brake and make sure the hood is closed.
3. Turn the engine off for at least 10 seconds.
4. PLACE YOUR FOOT FIRMLY ON THE BRAKE. This is VERY important, as the procedure will NOT
work if you do not have the brakes firmly engaged!
5. Go to the Diagnostics Menu->GM Commands->CASE Relearn menu on your DashHawk.
6. Start the vehicle and let the idle stabilize.
7. Follow the prompts on the DashHawk screen. When ready, hit ENTER to initiate the process.
8. When the DashHawk tells you to, steadily rev the engine up to approximately 4000 RPM until you feel the engine
stutter or “top out”.
9. IMMEDIATELY back off the throttle and let it return to idle.
Hope that helps!
Dave
