P0315
Fix within a few daysThe engine's computer (PCM) has not learned the crankshaft position system variation, which is essential for accurate misfire detection.
Code P0315 means your engine's computer hasn't learned the crankshaft position variation. Common causes: PCM relearn needed (70%), bad CKP sensor (20%). Drivability: Yes, but fix within days. Repair cost: $100-$300 DIY, $200-$600 professional.
Can I Drive With P0315?
Yes, for short trips only
Essential trips under 10 miles, avoid highways. Fix within a few days.
Stop driving immediately if: Flashing Check Engine Light, significant power loss, loud engine noises, or a strong smell of rotten eggs from the exhaust.
Symptoms of P0315
- 1Check Engine Light is on
- 2Engine misfires or runs rough
- 3Reduced engine power
- 4Engine may crank but not start
- 5Rough idle
Common Causes of P0315
Parts most likely causing this code, ranked by probability
After certain repairs like replacing the crankshaft position sensor, engine work, or flashing the PCM, the computer needs to learn the unique variations in the crankshaft's rotation for accurate misfire detection.
70% of P0315 cases are fixed by performing this relearn procedure
A faulty crankshaft position sensor sends incorrect or no signals to the PCM, preventing the system variation from being learned or causing misfires.
20% of P0315 cases are fixed by replacing the crankshaft position sensor
Damaged wiring, a loose connection, or corrosion in the CKP sensor circuit can disrupt the signal to the PCM, preventing the relearn procedure from completing.
5% of P0315 cases are fixed by repairing wiring or connectors
A rare but possible cause is an internal fault within the PCM itself, preventing it from performing or retaining the crankshaft position system variation learn.
5% of P0315 cases are fixed by replacing the PCM
Check These First (Before Buying Parts)
- Check for any other active or pending engine codes, especially those related to the crankshaft position sensor (P0335-P0339).
- Visually inspect the crankshaft position sensor's wiring harness and connector for any signs of damage, corrosion, or loose connections.
How to Diagnose P0315
- 1Connect an OBD-II scan tool to confirm P0315 and check for any other related codes (P0335-P0339).
- 2Visually inspect the crankshaft position sensor and its wiring harness for any signs of damage, fraying, or loose connections.
- 3Attempt to perform the 'Crankshaft Position System Variation Learn' procedure using a capable scan tool. Follow the specific instructions for your vehicle's make and model.
- 4If the relearn fails, test the crankshaft position sensor's signal and resistance according to manufacturer specifications.
- 5If the sensor tests good and the relearn still fails, diagnose the PCM for proper operation and power/ground connections.
P0315 on Popular Vehicles
Ford F-150
2004-2024Ford vehicles, including the F-150, frequently require a CKP relearn procedure after any work involving the crankshaft position sensor or PCM updates. This is a critical step for proper misfire detection.
75% fixed by performing the relearn procedure
Chevrolet Silverado
2007-2024Similar to Ford, GM trucks like the Silverado often trigger P0315 if the CKP relearn is not performed after sensor replacement or PCM service. A capable scan tool is necessary.
70% fixed by performing the relearn procedure
Honda Accord
2003-2024While less common than on domestic vehicles, Honda Accords can also set P0315, especially after a new CKP sensor or PCM replacement. The relearn procedure is essential.
65% fixed by performing the relearn procedure
Frequently Asked Questions
What does P0315 mean?
P0315 indicates that your vehicle's engine control module (PCM) has not successfully learned the crankshaft position system variation. This calibration is crucial for the PCM to accurately detect engine misfires.
Can I drive with P0315?
Yes, for short trips only. You can drive with P0315, but you should fix it within a few days. If the engine is misfiring severely or running very rough, limit driving to essential trips under 10 miles and avoid highways. Continued driving with unlearned variation can lead to misfire detection issues and potential damage.
Will P0315 clear itself?
No, P0315 will not clear itself. This code requires a specific 'Crankshaft Position System Variation Learn' procedure to be performed using a specialized scan tool. The PCM needs this calibration to function correctly.
How do I fix P0315 myself?
To fix P0315 yourself, you'll need a capable scan tool that can perform the 'Crankshaft Position System Variation Learn' procedure. First, check for any other related codes and inspect the crankshaft position sensor wiring. If the relearn fails, you might need to replace the crankshaft position sensor, which typically involves basic hand tools.
How much does it cost to fix P0315?
The cost to fix P0315 yourself ranges from $100-$300, primarily for a capable scan tool if you don't own one, plus the cost of a new crankshaft position sensor ($50-$150) if needed. Professional repair at a shop typically costs $200-$600, covering diagnostic time, the relearn procedure, and potential sensor replacement.
P0315 keeps coming back - why?
If P0315 keeps coming back, it means the 'Crankshaft Position System Variation Learn' procedure is either not completing successfully, or the PCM is failing to retain the learned data. This can be due to a faulty crankshaft position sensor, damaged wiring, an issue with the PCM itself, or not following the relearn procedure exactly.
Will P0315 fail emissions/smog test?
Yes, P0315 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most jurisdictions, and this code specifically indicates an issue with the engine's misfire monitoring system, which is a critical emissions component.
What's the difference between P0315 and P0335?
P0315 means the PCM hasn't learned the crankshaft position variation, which is a calibration issue. P0335, on the other hand, indicates a malfunction in the crankshaft position sensor circuit itself, meaning the PCM isn't receiving a proper signal from the sensor at all.
P0315 on Ford F-150?
On a Ford F-150, P0315 is a common code after replacing the crankshaft position sensor, performing engine work, or flashing the PCM. Ford vehicles are known to strictly require the 'Crankshaft Position System Variation Learn' procedure to be performed with a capable scan tool to clear this code and ensure proper engine operation.
Questions to Ask Your Mechanic
Did you perform the 'Crankshaft Position System Variation Learn' procedure after diagnosing the P0315 code?
Good answer: Yes, I used a factory-level scan tool to perform the CKP relearn. The procedure completed successfully, and the code has not returned.
What were the readings from the crankshaft position sensor before and after the relearn attempt?
Good answer: Before the relearn, the sensor showed consistent readings, but the PCM indicated the variation was not learned. After the relearn, the PCM confirmed the variation was learned and within specifications.
Repair Cost Estimate
DIY Repair
Parts only
$100-$300
Shop Repair
Parts + labor
$200-$600
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
0.5-2 hours
Intermediate - requires a specialized scan tool to perform the necessary relearn procedure, which is beyond basic DIY tools.
Cost of Waiting
Ignoring P0315 means your engine's computer cannot accurately detect misfires. Undetected misfires send unburned fuel into your exhaust, which can overheat and destroy your catalytic converter. A $50-$150 crankshaft position sensor or a $100-$300 scan tool investment now prevents a $800-$2,500 catalytic converter replacement later.
While You're In There...
If the relearn procedure consistently fails, the sensor itself is a likely culprit. Replacing it while diagnosing saves repeat labor.
Tools You'll Need
- OBD-II scan tool capable of performing 'Crankshaft Position System Variation Learn'
- Basic hand tools (sockets, wrenches) if replacing CKP sensor
- Multimeter (for testing CKP sensor or wiring)
P0315 is a common code, especially after certain repairs. It's usually a calibration issue that's straightforward to fix with the right tools, and your engine will run smoothly afterward.
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Your Next Steps
Step 1: Connect a capable OBD-II scan tool and attempt to perform the 'Crankshaft Position System Variation Learn' procedure. Follow your vehicle's specific instructions carefully.
Step 2: If the relearn fails, visually inspect the crankshaft position sensor and its wiring. If no obvious damage, test the sensor's resistance and signal output with a multimeter.
Step 3: If the sensor tests faulty or the relearn still won't complete, you'll likely need a new crankshaft position sensor. After replacement, repeat the relearn procedure.