Crankshaft Position System Variation Not Learned
What does P0315 mean?
The P0315 code means the vehicle's onboard diagnostic system has detected: Crankshaft Position System Variation Not Learned. This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated
- Engine may run rough at idle
- Slight hesitation during acceleration
- Intermittent misfire codes present
- Engine may stall occasionally
Probable Causes (Ranked by Likelihood)
- Crankshaft position variation relearn procedure not performed after repair Very High
- Faulty crankshaft position sensor High
- Damaged or worn reluctor ring on crankshaft Moderate
- Excessive crankshaft end play Moderate
- PCM software needs update Low
Step-by-Step Diagnostic Procedure
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Perform the crankshaft position variation relearn procedure using a scan tool -- follow manufacturer-specific steps
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For GM vehicles: warm the engine, apply brakes, then accelerate to the specified RPM until the scan tool confirms relearn
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If relearn fails, inspect the crankshaft position sensor for damage, correct air gap, and secure mounting
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Check the reluctor ring (tone ring) on the crankshaft for missing or damaged teeth
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Verify there is no excessive crankshaft end play using a dial indicator
Frequently Asked Questions
Can I drive with code P0315?
You can drive short distances. The engine should run reasonably well but may have slight drivability issues. The relearn procedure should be performed as soon as possible.
What is a crankshaft position variation relearn?
It is a procedure where the PCM learns the unique characteristics of your crankshaft reluctor ring. This is required after certain repairs like crankshaft sensor replacement, PCM replacement, or engine work.
Is P0315 mainly a GM issue?
Yes. This code is most commonly seen on GM vehicles (Chevrolet, GMC, Cadillac, Buick) that require a specific relearn procedure. Other manufacturers handle crankshaft learning differently.