P0315: Crankshaft Position System Variation Not Learned
What to do
The car will usually drive normally, but misfire detection is compromised until the relearn is done. Any workshop with a capable scan tool can perform it.
What this code means
Misfire detection works by measuring tiny changes in crankshaft speed, which means the module must first learn the manufacturing variation in the reluctor wheel itself — otherwise normal machining tolerance reads as a misfire. This code says that learning procedure has not been completed. It commonly appears after a crankshaft sensor, engine or control module has been replaced, and is cleared by performing the relearn with a scan tool rather than by fitting parts.
Likely causes
Start here
Less common
- Faulty crankshaft position sensor · moderate
- Damaged reluctor or tone ring · specialist
Rare
- Control module software fault · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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