Crankshaft Position System Variation Not Learned
The P0315 code indicates that the Engine Control Module (ECM) has not learned the crankshaft position sensor variation, which is necessary for accurate misfire detection and fuel injection timing. This learning process compensates for manufacturing tolerances in the crankshaft and sensor wheel. The code is typically set after a battery replacement, ECM replacement, or if the relearn procedure was interrupted.
01. Most Common Causes
- Battery or ECM replacement without performing the relearn procedure
- Interrupted or incomplete crankshaft variation relearn
- Faulty crankshaft position sensor or wiring issues
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine may run rough or misfire
- Reduced fuel economy and performance
03. Step-by-Step Diagnosis
Step 1: Connect a scan tool and verify the P0315 code. Check for any other related codes.
Step 2: Perform the crankshaft position variation relearn procedure using a professional scan tool that supports bidirectional control.
Step 3: If the relearn fails, inspect the crankshaft position sensor, wiring, and connector for damage or corrosion. Replace if necessary.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally not recommended to drive for extended periods as the ECM cannot accurately detect misfires, which could lead to catalytic converter damage or poor engine performance.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for the relearn procedure at a shop. If a sensor replacement is needed, costs can be higher.