P0315 Code: Crank Variation Not Learned — Causes & Fix
P0315 means the crankshaft position system variation has not been learned — the ECM needs this relearn to accurately detect misfires.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $80 – $600
- Time to fix
- 30 minutes – 2 hours
What it means
Causes are usually a missed relearn after a repair/battery/ECU service; occasionally a crank sensor or reluctor fault. P0315 is a generic OBD-II code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer OBD-II vehicle regardless of make. Fix the underlying fault, then clear the code with an OBD-II scan tool — it will return if the problem isn't resolved.
Symptoms
- Check engine light on
- Often paired with misfire codes
- Little direct drivability effect
How to fix it
- 1
Perform the crank relearn
1. Run the crankshaft variation relearn procedure with a scan tool.
- 2
Check the crank sensor
1. If the relearn fails, inspect the crank sensor and reluctor ring. 2. Repair, relearn, then clear the code.
Frequently asked questions
Why does P0315 need a relearn?
After certain repairs or a reflash, the ECM must relearn small crank-signal variations to detect misfires. A scan-tool procedure does it.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.