What this code means
P0315 means the ECM may not have a learned crankshaft position variation value stored.
What the vehicle may do
- The vehicle may turn on the check engine light.
- The engine may appear to run normally while the code is stored.
- Misfire detection can be affected because the ECM often uses the learned crank variation value as part of that calculation.
Possible fault areas
- A crankshaft position variation learn that may not have been completed.
- Possible battery readiness issues that can interfere with completing the learn procedure.
- Possible ECM learn-status or memory handling concerns.
- Possible crankshaft position signal variation context that may need the learn value stored correctly.
Diagnostic path
Opening context
On this 2014 to 2018 GMC Sierra 1500 with the 5.3 gas engine, P0315 means the crankshaft position variation has not been learned. That learned value lets the ECM compensate for small crankshaft and crank sensor tolerance differences, which helps it recognize misfire events correctly. The customer may only notice a check engine light, and the possible fault area is usually around the learn status, the conditions needed to perform the learn, battery readiness, or the ECM storing that learned value.
Set up the diagnostic path
Start with the basic system checks and keep the diagnostic approach structured. Before running the learn, make sure the vehicle battery has passed a load test and is completely charged. This matters because the next step depends on the scan tool completing the crankshaft position variation learn cleanly.
Run the crank variation learn
With the ignition on and the vehicle in Service Mode, use the scan tool to perform the crankshaft position variation learn. This is the main action for P0315 because the setting condition is that the crankshaft position variation learn is not learned.
Reproduce the monitor conditions
After the learn, operate the vehicle under the conditions that allow the code to run. In plain terms, the engine needs to be running, and the monitor runs continuously once its conditions are met. If you have captured operating conditions from when the code set, use those same conditions to help confirm the result.
Decision point
Now verify that P0315 does not reset. If the code sets again after the learn and the drive conditions are met, the directed repair is to replace the K20 Engine Control Module. If the code does not set, the result is all OK.
Repair verification and close
After any repair is completed, verify the repair and confirm the code stays gone. Takeaway: for P0315, complete the crankshaft position variation learn, run the conditions that allow the monitor to check it, and only follow the ECM replacement path if the code sets again. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0315 is often handled by completing the crankshaft position variation learn, then verifying that the code does not return under the proper operating conditions.
For more guided automotive diagnostics, visit STEP Diagnostics.
