P0315 Code: Run the Relearn Before Buying Any Crank Sensor

Q: Can I drive with a P0315 code?

Yes, in most cases — but address it within days, not weeks. P0315 itself doesn't damage the engine or make it unsafe to drive. The bigger concern is that P0315 disables the misfire detection system: the PCM uses the crankshaft variation data to detect misfires, and without it, real misfires from other causes (failing coils, bad injectors, low compression) won't trigger the appropriate misfire codes. You could be experiencing engine damage from undetected misfires while P0315 is active. Diagnose and fix promptly to restore full engine protection.

Q: What's the difference between P0315 and P0335?

Both involve the crankshaft position sensor but represent very different problems. P0335 = crankshaft position sensor circuit malfunction (electrical issue — sensor failed, wiring open or shorted, no signal reaching PCM). P0315 = crankshaft position SYSTEM variation not learned (software issue — sensor signal is reaching PCM fine, but the PCM hasn't completed the relearn procedure to calibrate the unique trigger wheel pattern for this engine). P0335 needs a sensor or wiring fix. P0315 usually just needs a scanner command (relearn procedure). Both can co-occur if a sensor was replaced without performing relearn afterward.

Q: Why do I need to perform a relearn procedure?

Every crankshaft trigger wheel has tiny manufacturing variations — the spacing between teeth isn't perfectly identical. From the factory, the PCM 'memorizes' this exact pattern as a baseline so it can use deviations from the pattern to detect misfires accurately. Three events reset this memory and require a new relearn: (1) battery disconnection — PCM loses learned values on some platforms; (2) PCM replacement or software update; (3) replacement of the CKP sensor, crankshaft, flywheel/flexplate, or timing components. Without a successful relearn, the PCM operates on default values which trigger P0315 and disable misfire detection.

Q: How much does it cost to fix P0315?

If relearn alone fixes it (70% of cases): $0 with a bidirectional scanner DIY, or $80-$150 if a shop performs the procedure. CKP sensor replacement: $30-$80 in parts ($150-$300 at a shop with relearn included). Wiring repair: $15-$80. Timing component repair (worst case): $500-$2,000+ for timing chain or trigger wheel work. Most P0315 cases resolve under $200. The single biggest cost-saver: owning or borrowing a bidirectional scanner with relearn capability. The 5-minute software fix prevents 70% of cases from becoming expensive part-replacement chains.

Q: What scanner do I need to fix P0315?

You need a BIDIRECTIONAL scanner that can send the manufacturer-specific crankshaft relearn command. Basic code readers and most generic scanners can only READ codes — they cannot send commands to the PCM. The iCarzone UR1000 is a 7-inch Android tablet diagnostic scanner at $499.99 with full bidirectional control, manufacturer-specific relearn procedures (GM CASE Learn, Dodge crankshaft relearn, Ford procedure, Toyota relearn), live data graphing, and broad coverage including GM 5.3L V8 trucks, Dodge Ram, Jeep, Ford F-150, BMW, and most European platforms. The relearn capability alone often saves the cost of the scanner on a single P0315 case.

Q: Why does P0315 set after I disconnect the battery?

Some platforms — especially GM 5.3L V8 trucks and certain Dodge HEMI engines — store the crankshaft variation learned values in volatile PCM memory that resets when battery power is lost. When you reconnect the battery, the PCM has lost its calibrated reference values and immediately sets P0315 until you complete a new relearn procedure. This is why mechanics performing battery service on these platforms should always be prepared to run the relearn afterward. If you've had a recent battery service and now have P0315, this is almost certainly the cause — run the relearn first before any other diagnosis.

Q: Can a bad timing chain cause P0315?

Yes, but it's rare. A stretched timing chain (especially common on GM 3.6L V6 LFX/LGX, Mazda SkyActiv 2.0L/2.5L, and BMW N20/N26 engines) shifts the camshaft position relative to the crankshaft by enough that the PCM can't reliably correlate the two sensor readings — preventing successful relearn. Symptoms beyond just P0315: P0008/P0009 (timing chain stretch codes), P0016/P0017 (crank-cam correlation codes), engine noise that worsens with mileage, harder cold starts. Timing chain replacement is $500-$2,000 depending on engine — not a cheap fix, but ignoring it leads to catastrophic timing failure.

Q: Why does P0315 affect misfire detection?

Modern engines detect misfires by watching for tiny RPM drops as each cylinder fires. The PCM measures the time between trigger wheel teeth passing the crank sensor — when a cylinder fails to fire, that segment is slightly slower than the others. But this only works if the PCM knows the BASELINE timing of each tooth segment, which is what the relearn procedure stores. Without it, the PCM can't distinguish 'normal manufacturing variation' from 'misfire' — so misfire monitoring is disabled until P0315 clears. Real misfires from other problems may go undetected, allowing them to damage catalytic converters or engine internals while you remain unaware.

⚡ QUICK ANSWER

P0315 means "Crankshaft Position System Variation Not Learned" — the PCM does not have a stored baseline of the crankshaft trigger wheel's tooth pattern. Critical insight: this is overwhelmingly a software state, not a hardware failure. Every engine's trigger wheel has tiny manufacturing variations between teeth, and the PCM "memorizes" this exact pattern as a baseline for misfire detection. When that memory is lost (battery disconnect, PCM update, sensor replacement, timing component service), the PCM operates without it and sets P0315 until a relearn procedure is performed. Fix priority: (1) run the manufacturer-specific relearn procedure with a bidirectional scanner — 70% of cases stop here, (2) if relearn fails to complete, diagnose what's preventing it, (3) only then consider parts replacement.

What Does P0315 Actually Mean?

Your engine's crankshaft position sensor (CKP) reads pulses from a toothed trigger wheel (reluctor ring) that spins with the crankshaft. The PCM uses these pulses to track exactly where the crankshaft is in its rotation cycle, which controls ignition timing, fuel injection, and misfire detection. But here's the catch: every trigger wheel has tiny manufacturing variations — the spacing between teeth isn't perfectly identical. These variations are smaller than 1 degree of rotation, but they're measurable, and they matter for misfire detection accuracy.

From the factory, the PCM runs a learn procedure to memorize the unique tooth-spacing pattern of THIS specific engine's trigger wheel. After learning, the PCM can detect misfires by watching for RPM variations that deviate from the learned baseline. When a cylinder fails to fire, the next tooth pulse arrives slightly later than the baseline pattern predicts — that's how the PCM identifies misfires. P0315 sets when this learned baseline is missing from PCM memory. Without it, the PCM can't distinguish "normal manufacturing variation" from "actual misfire" — so misfire monitoring is disabled until the relearn is performed.

P0315 vs P0335 — same sensor, different problems: P0335 = Crankshaft Position Sensor "A" Circuit Malfunction. Electrical/hardware issue: sensor failed, wiring broken, no signal reaching PCM. P0315 = Crankshaft Position System Variation NOT LEARNED. Software/calibration issue: signal is fine, but PCM hasn't memorized this engine's unique trigger pattern. P0335 needs hardware fix. P0315 needs scanner command (usually). They can co-occur when a sensor is replaced without performing relearn afterward.

Critical: P0315 is the OBD-II code most commonly associated with unnecessary part replacements. The "system variation not learned" language sounds like a serious mechanical fault, but it's almost always a software state. NEVER authorize CKP sensor replacement, flywheel work, or timing chain repairs on P0315 alone without first attempting the relearn procedure. If a shop quotes parts before they've tried (and documented) a relearn attempt, get a second opinion.

What Are the Symptoms of P0315?

P0315 produces surprisingly mild symptoms because it doesn't directly affect engine operation — it just disables misfire monitoring:

Check Engine Light — steady; usually the ONLY visible symptom

No driveability issues in most cases — engine runs and accelerates normally

Misfire detection disabled — real misfires may go unreported

Slight rough idle (occasional) — only on platforms that affect spark timing too

Minor fuel economy decrease — 1-3 MPG, often unnoticeable

Recent service event in history — battery, PCM, sensor, or timing work

Failed emissions inspection — readiness monitors won't complete

Code appears suddenly after no problems — characteristic post-service pattern

The "recent service" tell: If P0315 appeared shortly after a battery replacement, PCM update, sensor swap, or any work involving the crankshaft, flywheel, or timing components, your diagnosis is essentially complete — the relearn procedure was almost certainly missed. Run the relearn first (Step 2) before any other diagnostic. About 70% of "recent service" P0315 cases resolve immediately with a 5-minute scanner command.

Is P0315 Code Serious?

Moderate severity — not an emergency, but address within a week. The code itself doesn't damage anything, but its consequences can:

Misfire detection disabled — real misfires from OTHER causes won't be flagged

Catalyst damage risk — undetected misfires can destroy the catalytic converter

Failed emissions inspection — guaranteed until cleared

Possible accelerated engine wear — if undetected misfires persist

Unnecessary parts purchase risk — if misdiagnosed by shop

The good news: P0315 is usually one of the cheapest codes to fix when diagnosed properly — often $0 with a bidirectional scanner. The bad news: if misdiagnosed as a "bad sensor" or "bad flywheel," it can become one of the most expensive misdiagnoses on the OBD-II list (up to $2,000 for unnecessary timing or flywheel work). Diagnostic order matters more on this code than almost any other.

Severity rating: 🟡 Moderate — diagnose within 1-2 weeks. The code itself isn't urgent, but the disabled misfire detection means you may not get warning of OTHER engine problems. Address promptly to restore full engine monitoring. Get the relearn procedure done before driving long distances.

What Causes a P0315 Code? (Ranked by Frequency)

Cause distribution heavily favors procedure-related (software) issues over actual parts failure:

Relearn Procedure Not Performed (40% of Cases)

Most common scenario. Recent service touched the crankshaft system (battery disconnect, PCM reflash, software update, even some EVAP repairs that disconnect battery briefly) but the technician didn't perform the required relearn afterward. Symptom: P0315 appears immediately after recent service with no other codes. Fix: run the manufacturer-specific relearn procedure with a bidirectional scanner. 5 minutes. No parts needed. By far the cheapest OBD-II "repair" on the entire diagnostic tree.

Fix: $0 DIY (with bidirectional scanner)

CKP Sensor Replaced Without Relearn (15-20% of Cases)

The crankshaft position sensor was replaced (often correctly, for an actual P0335 sensor failure), but the technician forgot or didn't know about the mandatory relearn procedure that must follow CKP sensor replacement. The new sensor produces signal pulses but at slightly different timing than the old one, and the PCM no longer has accurate baseline calibration. Fix: run relearn procedure. Often documented as "after-repair P0315" in service records.

Fix: $0 DIY relearn (with bidirectional scanner)

Battery Replacement Without Relearn (10-15% of Cases)

Specific to platforms that store learned values in volatile PCM memory (notably GM 5.3L V8, some Dodge HEMI, certain BMW). Battery disconnect erases the crankshaft variation baseline. New battery is installed, vehicle starts and runs normally, but P0315 sets within minutes because the PCM has no learned reference. Most common scenario for high-mileage vehicles getting battery service. Fix: run relearn after every battery service on these platforms.

Fix: $0 DIY relearn after battery service

Failed CKP Sensor (10-15% of Cases)

The crankshaft position sensor has actually failed — internal hall-effect circuit damaged, magnetic element weakened, or wiring connection within the sensor broken. Distinctive symptom: P0315 + P0335 (sensor circuit) together; relearn procedure fails to complete because the PCM can't get consistent signal pulses to baseline. Test sensor electrically before replacing — many "bad sensors" are actually wiring or connector issues. OEM only; aftermarket CKP sensors are notorious for failure-from-new.

Fix: $30–$80 OEM sensor + relearn

Wiring or Connector Issues (5-8%)

CKP sensor wiring is exposed to engine bay heat and vibration. Common damage: chafed insulation against exhaust components, melted connector plastic from heat, oil contamination from valve cover or oil pan leaks, corrosion at terminal pins. Symptoms: intermittent P0315 that comes and goes, sometimes worse after warm-up. Inspect connector and wiring; clean corroded pins; apply dielectric grease; repair chafed wires with soldered splice.

Fix: $15–$80 wiring repair

Worn Flywheel / Flexplate Teeth (3-5%)

The starter ring gear teeth on the flywheel (manual transmission) or flexplate (automatic) provide the CKP sensor pulses on some engines. Worn teeth — often from a degraded starter motor or after many starts over 200,000+ miles — produce inconsistent pulses that prevent successful relearn. Inspect through the starter hole with the starter removed. Replacement requires transmission removal — expensive labor.

Fix: $400–$1,500 flexplate + labor

Stretched Timing Chain (3-5%)

A stretched timing chain (common on GM 3.6L V6 LFX/LGX, Mazda SkyActiv 2.0L/2.5L, BMW N20/N26 engines) shifts the camshaft position relative to the crankshaft by enough that the PCM can't reliably correlate the two sensor readings. Symptoms: P0315 + P0008/P0009 (timing chain stretch) + P0016/P0017 (correlation codes). Cold-start engine noise that improves as oil pressure builds. Timing chain replacement is expensive but mandatory — ignoring leads to catastrophic timing failure.

Fix: $500–$2,000 timing chain job

PCM Software / Calibration Issue (2-3% — Rare)

Some platforms have had software bugs causing false P0315 even after successful relearn. Free reflash at dealer typically resolves; often under federal emissions warranty. Check VIN at NHTSA for applicable TSBs before any hardware work. Actual PCM hardware failure causing P0315 is essentially never the cause — don't let any shop talk you into PCM replacement on this code.

Fix: $0–$200 PCM reflash

What You'll Need

Tools

BIDIRECTIONAL OBD2 scanner with relearn function iCarzone UR1000 ›
Digital multimeter (CKP sensor testing)
Battery maintainer (stable voltage during relearn)
Wiring diagram for your specific vehicle
Safe area for drive cycle (closed road or empty highway)
Sensor socket (typically 8mm or 10mm — varies)

Possible Parts & Supplies

OEM CKP sensor (only if testing confirms failure) $30–$80
Connector pigtail (if heat-damaged) $15–$60
Dielectric grease $5–$10
Sensor mounting O-ring (some engines) $3–$8
Flexplate (worst non-timing case) $100–$300 + labor
Timing chain kit (worst case) $200–$600 + labor

Recommended Diagnostic Tool for P0315

iCarzone UR1000 — 7" Android Tablet OBD2 Diagnostic Scanner

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7-inch Android tablet scanner with full bidirectional control — the essential feature for P0315. Send manufacturer-specific crankshaft relearn commands (GM CASE Learn, Dodge Crankshaft Variation Learn, Ford procedure, Toyota relearn). Without this capability, you cannot fix P0315 without going to a dealer. Live data graphing displays CKP signal patterns during relearn to verify successful completion. Saves $100-$200 per visit on relearn services. Wide platform coverage including GM 5.3L V8 trucks, Dodge Ram, Jeep Grand Cherokee, Ford F-150, BMW, and most European platforms.

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How Do You Fix a P0315 Code?

Follow these steps in order. Step 2 (relearn procedure) resolves about 70% of cases with no further diagnosis needed.

P0315 Diagnostic Flowchart — Decision Tree

Figure 1: P0315 diagnostic decision tree — Step 2 alone resolves 70% of cases. Most diagnostic paths don't go past Step 2. CKP sensor replacement is the LAST resort, not the first action.

1
Scan All Codes and Check Recent Service History

Plug in your scanner and record every code. Then ask the owner about recent service — this is uniquely important for P0315 because it's overwhelmingly a "recent service" code:
- P0335 (CKP sensor circuit) — actual sensor problem; needs Step 4 testing
- P0300-P0308 (misfires) — common with P0315 because misfire detection is impaired
- P0340/P0341 (camshaft position sensor) — PCM cross-checks both; correlation issues
- P0008/P0009 (timing chain stretch — GM 3.6L LFX/LGX) — points to Step 5
- P0016/P0017 (crank-cam correlation) — timing component issue
Recent service history that triggers P0315:
- Battery replacement or disconnect — most common; especially GM 5.3L V8, Dodge HEMI
- PCM/ECM update or replacement — automatic for major service
- CKP sensor replacement — relearn always required after sensor swap
- Timing component work — chain, gears, sprockets
- Flywheel/flexplate replacement — full relearn mandatory
- Crankshaft replacement — rare, but relearn always needed
If ANY of these match recent service, go directly to Step 2 — 70%+ chance the relearn alone fixes the code.
2
Run the Crankshaft Relearn Procedure — The Single Most Important Step

This is the entire P0315 diagnosis in 5 minutes. Requires a BIDIRECTIONAL scanner with manufacturer-specific commands. Basic code readers cannot perform this procedure.

General procedure pattern (specifics vary by platform):
- Engine at FULL operating temperature — coolant must read at least 176°F (80°C). Drive vehicle 15+ minutes first if needed.
- Battery voltage above 12.0V — connect a battery maintainer if uncertain. Low voltage during relearn often causes abort.
- All accessories OFF — A/C, headlights, radio, blower fan
- Vehicle in PARK with parking brake set
- Connect bidirectional scanner and navigate to the manufacturer-specific procedure:
- → GM platforms: "CASE Learn" or "Crank Variation Learn"
- → Dodge/Jeep: "Crankshaft Variation Learn"
- → Ford: "Crankshaft Profile Learn"
- → Toyota: "Crankshaft Position Sensor Learn"
- Follow on-screen prompts exactly — most procedures require specific RPM ranges or acceleration patterns
Specific GM 5.3L V8 procedure (most common platform):
- With scanner showing "Cylinder Power Balance" or "CKP Variation Learn" command, initiate the procedure
- Apply brake pedal, place transmission in NEUTRAL, release brake
- When prompted, accelerate to redline (typically 4,000-5,500 RPM range)
- Release throttle and allow vehicle to decelerate under engine braking through fuel cut-off
- Scanner displays "CKP Variation Learned" when procedure completes successfully
If the relearn completes successfully, you're DONE. Clear codes, drive 5-10 miles for monitor reset, and verify P0315 doesn't return. About 70% of P0315 cases stop here with zero parts cost. The remaining cases — when relearn FAILS to complete — go to Step 3.
3
If Relearn Fails to Complete — Diagnose Why

If the procedure aborts with "Not Learned" status, the issue isn't missing relearn — something's preventing successful completion. Document exactly which step aborts:
- Aborts immediately upon starting = engine not at operating temperature OR battery voltage too low. Re-verify both conditions and retry.
- Aborts during RPM acceleration = engine misfire preventing stable RPM reference (look for accompanying P0300 codes), OR CKP sensor signal too noisy
- Aborts after RPM stabilizes = signal-level issue with CKP sensor (Step 4), or PCM software bug (Step 8 — TSB check)
- Scanner shows "communication error" = scanner can't talk to PCM properly; may need scanner update or VIN-specific software
- Repeated attempts give different results = intermittent signal, usually wiring or connector issue (Step 4)
Also verify: was a TSB checked for this VIN? Some platforms (especially 2014-2018 GM 5.3L V8) have software TSBs that fix P0315 issues with calibration update — free at dealer.
4
Test the CKP Sensor Electrically

If relearn won't complete, test the crankshaft position sensor before replacing:
- Locate CKP sensor — typically on engine block near the crankshaft pulley or on the bell housing side facing the flywheel
- Visual inspection — disconnect connector, check pins for corrosion, melted plastic, oil contamination, broken locking tab
- 5V reference voltage test (most CKP sensors are 3-wire) — key on engine off, measure between two of the pins; should read 4.95-5.05V. Below = reference circuit problem
- Signal voltage during cranking — back-probe signal wire while cranking engine; should see AC voltage pulses (typically 0.5-5V depending on RPM); flat reading = sensor failed or has lost magnetic field
- Resistance test (hall-effect sensors): consult service manual for spec, typically 200-1500Ω between specific pins
- Continuity test: with battery disconnected, verify signal wire continuity from sensor connector to PCM connector. Above 5Ω = wiring damage
A failed CKP sensor produces inconsistent or no signal during cranking, which is exactly what prevents relearn from completing.
5
Inspect Trigger Wheel and Timing Components

If the CKP sensor tests good but relearn still fails, the mechanical reference (trigger wheel) may be damaged or shifted:
- Remove CKP sensor and visually inspect trigger wheel through the sensor hole using a flashlight and inspection mirror
- Look for: bent teeth (from impact), missing teeth (from corrosion or damage), debris stuck between teeth, wear from a misaligned sensor
- For flywheel/flexplate trigger: starter ring gear teeth show wear from a degraded starter; rotate crankshaft slowly and inspect all teeth
- Timing chain stretch test: compare crankshaft TDC mark against camshaft sprocket alignment marks; stretched chain shifts cam position. Especially common on GM 3.6L LFX/LGX (2010-2019), Mazda SkyActiv 2.0L/2.5L, BMW N20/N26
- If timing components were recently serviced: verify proper installation — wrong sprocket orientation or one-tooth-off timing produces P0315 that won't clear
Damaged trigger wheel or stretched timing chain requires major engine disassembly. This is the most expensive P0315 cause but also the rarest (combined < 8% of cases). Verify thoroughly before authorizing this level of repair.
6
Replace CKP Sensor (Only If Step 4 Confirms Failure) and Re-Run Relearn

Only after Step 4 testing confirms the CKP sensor has failed should you replace it:
- Use OEM only. AC Delco for GM, Motorcraft for Ford, Mopar for Dodge, NGK/NTK for Toyota. Aftermarket CKP sensors are notorious for failure-from-new and signal noise that prevents successful relearn
- Disconnect battery negative 5 minutes before sensor removal — prevents shorts during the swap
- Sensor removal: usually held by 1 or 2 small bolts (8mm or 10mm typically). Some have a sealing O-ring that should be replaced with the sensor
- Inspect mounting hole for debris before installing new sensor — even small particles can cause signal interference
- Apply dielectric grease to connector pins before reconnecting; helps prevent future corrosion-related signal issues
- RELEARN IS MANDATORY after CKP sensor replacement. Without it, P0315 returns within one drive cycle. Run the full relearn procedure (Step 2) immediately after installation.
- Clear codes and road test 10+ miles including a variety of RPM ranges. P0315 should not return.
If P0315 returns after sensor replacement plus relearn, double-check: (1) Did you actually complete the relearn? Some procedures require multiple driving conditions to fully learn. (2) Was the aftermarket sensor a quality issue? Swap to genuine OEM if you used aftermarket. (3) Are there accompanying codes (P0008, P0009, P0016) pointing to timing issues? About 15-20% of repeat-failure P0315 cases trace to overlooked timing chain stretch.

How Much Does P0315 Cost to Fix?

P0315 has the widest cost range of any common OBD-II code — $0 (just a scanner command) to $2,000+ (timing chain or flexplate). About 70% of cases fall in the $0-$50 range when diagnosed properly.

Repair	DIY Cost	Shop Cost	You Save	Type
Crankshaft relearn procedure (FIXES 70% of cases)	$0 (with bidirectional scanner)	$80–$150	Up to $150	5-min Software Fix
Connector cleanup + dielectric grease	$5–$10	$60–$120	Up to $115	DIY Easy
PCM software reflash (TSB)	N/A (dealer)	$0–$200 (often free)	—	Dealer / Free
CKP sensor wiring splice	$15–$60	$150–$300	Up to $285	DIY Moderate
Connector pigtail replacement	$15–$60	$150–$300	Up to $285	DIY Moderate
CKP sensor replacement + relearn (OEM)	$30–$80	$200–$400	Up to $370	DIY Friendly
Flexplate / flywheel replacement	$100–$300 part	$800–$1,800 with labor	Up to $1,500	Shop Required
Timing chain replacement (GM 3.6L)	$200–$600 parts	$1,500–$2,500	Up to $1,900	Shop Required
Timing chain replacement (BMW N20)	$400–$800 parts	$1,800–$3,500	Up to $2,700	Shop Required

The diagnostic ROI: The $499 UR1000 scanner with bidirectional relearn capability pays for itself on a single P0315 case. The relearn command is $80-$150 at any dealer or independent shop with proper equipment. After 4-5 P0315 services for yourself, friends, or family, the scanner has paid for itself. And many P0315 cases that look complex are just missing relearns — without bidirectional capability, you'd be at the mercy of dealer pricing.

Per the EPA's emissions standards ↗ EPA Vehicle Emissions I/M Program, a vehicle with an active P0315 code will fail OBD-II emissions inspection — the misfire monitor cannot complete its readiness check. CKP sensor replacement is sometimes covered under powertrain warranty on newer vehicles. Verify with your dealer using VIN before paying out of pocket.

Which Vehicles Are Most Prone to P0315?

P0315 appears across nearly all OBD-II vehicles built since the late 1990s, but two platform groups generate disproportionate volume: GM 5.3L V8 trucks (CASE relearn culture problem) and Dodge Ram / Jeep Grand Cherokee (HEMI battery-disconnect sensitivity). Deep-dives below.

Make	Model / Engine	Years	Primary Cause & Notes	Risk
GM / Chevrolet / GMC / Cadillac	Silverado, Sierra, Tahoe, Suburban, Yukon, Escalade (4.8L, 5.3L, 6.0L, 6.2L V8)	2007–2024	Most-frequent missing CASE relearn after battery service. See GM deep-dive.	High
Dodge / Ram / Chrysler / Jeep	Ram 1500/2500, Charger, Challenger, Grand Cherokee, Wrangler, Durango (5.7L HEMI, 6.4L HEMI, 3.6L Pentastar)	2009–2024	Battery-disconnect sensitivity; relearn always required. See Dodge deep-dive.	High
Ford / Lincoln	F-150, Mustang, Explorer (3.5L EcoBoost, 5.0L Coyote, 2.7L EcoBoost)	2011–2024	P0315 after sensor replacement or major service.	Medium
GM	Camaro, ATS, CTS, XT5, Acadia, Colorado (3.6L LFX/LGX V6)	2010–2019	Timing chain stretch causes P0315; multiple TSBs; expensive repair.	Medium
Mazda	Mazda3, Mazda6, CX-5, CX-9 (2.0L, 2.5L SkyActiv)	2014–2024	SkyActiv timing chain stretch; relearn often won't complete with stretched chain.	Medium
BMW	3 Series, 5 Series, X3, X5 (N20, N26, B48)	2012–2024	Timing chain stretch on N20/N26 a known issue; expensive fix.	Medium
Toyota / Lexus	Tundra, Tacoma, 4Runner, Sequoia (1GR-FE V6, 3UR-FE V8)	2007–2024	Lower volume; usually procedure-related after dealer service.	Low
Honda / Acura	Civic, Accord, Pilot, MDX (various)	2008–2024	Rare; usually post-CKP-sensor-replacement.	Low

P0315 on GM 5.3L V8 Trucks (The CASE Relearn Culture Problem)

GM 5.3L V8 trucks (Silverado 1500, Sierra 1500, Tahoe, Suburban, Yukon, Escalade) generate the highest absolute volume of P0315 cases — for a uniquely cultural reason as much as a technical one:

1. The CASE relearn is widely forgotten. GM uses a procedure called "CASE Learn" (Crankshaft Angle Sensor Error learn) that must be performed after battery disconnect, PCM service, or CKP sensor replacement on most 4.8L/5.3L/6.0L V8 trucks from 2007-2024. The relearn requires accelerating to fuel cut-off (around 5,500 RPM in 1st or 2nd gear) under scan tool control. Many independent shops don't know this procedure exists, don't have the bidirectional capability to run it, or skip it to save time. Result: customer gets the truck back, drives 50 miles, and P0315 sets. This is by far the most common P0315 scenario in North America.

2. The battery-disconnect sensitivity. GM 5.3L V8 platforms lose CASE Learn calibration on virtually every battery disconnect — meaning EVERY battery replacement, EVERY trickle-charger session that fully discharges and recovers, even some quick-jump scenarios. A 2014 Silverado that's never had any other work but recently got a new battery is almost certainly P0315 from the battery alone. Free fix with bidirectional scanner: 5 minutes.

3. AFM/DFM oil consumption complication. If your GM 5.3L also has the well-documented AFM/DFM oil consumption issue, P0315 may appear alongside P0010/P0014 (camshaft codes), P0420 (catalyst efficiency), or P0300 (misfires). These engines deserve a comprehensive diagnostic — not just throwing relearn at the symptom. Address oil consumption issues separately if present.

GM 5.3L V8 action plan: If you have P0315 on a GM 5.3L V8 truck, run CASE Learn FIRST before any other diagnosis. The procedure is identical across 2007-2024 with minor variations. Bidirectional scanner required (UR1000 supports this). Engine must be at operating temperature, A/C off, in PARK, then NEUTRAL acceleration to fuel cut-off under scanner control. If CASE Learn completes successfully, you're done — no parts needed. About 60-65% of GM 5.3L P0315 cases stop here.

P0315 on Dodge Ram, Charger, Challenger, Jeep Grand Cherokee (HEMI Battery Sensitivity)

Stellantis platforms with the 5.7L HEMI V8 (Ram 1500/2500, Charger, Challenger, Jeep Grand Cherokee, Wrangler, Durango) generate the second-highest P0315 volume. Two distinct patterns:

1. The HEMI battery-disconnect epidemic. Similar to GM 5.3L but even more sensitive — virtually any voltage event resets the learned crankshaft variation values. Replacing a battery? P0315 within minutes. Letting the battery die overnight and jumping it? P0315. Some Mopar reflash procedures will set P0315 on completion if the technician forgets the post-flash relearn. The fix is identical — bidirectional scanner sends "Crankshaft Variation Learn" command, follow the prompts, done in 5 minutes.

2. The PCM water intrusion complication (2009-2018 Ram 1500/2500). Ram trucks mount the PCM on the firewall near the heater core drainage area. Water from clogged sunroof drains can pool on the PCM and corrode connector pins (also a P0607 trigger). If P0315 appears with intermittent symptoms or alongside P0607, check the PCM area for water staining before any sensor work.

3. Grand Cherokee 3.6L Pentastar (2011-2019) timing chain stretch. Less common but real: the 3.6L Pentastar has documented timing chain stretch issues on certain production years. P0315 + P0008/P0009 (timing chain stretch) + P0016/P0017 (correlation codes) together strongly suggests stretch. Mileage 100,000+. Cold-start engine noise that improves as oil pressure builds. This is the expensive scenario — $1,500-$2,500 timing chain job.

Dodge/Ram action plan: Step 2 relearn first ALWAYS on any HEMI-equipped vehicle. If relearn won't complete on a 2009-2018 Ram, check PCM connector area for water damage (firewall location). For 2011-2019 Grand Cherokee 3.6L Pentastar with cold-start noise + P0315 + P0008/P0009, suspect timing chain stretch — confirm with diagnostic before any sensor work.

How to check for a TSB: Visit NHTSA.gov ↗, enter your VIN. Search for "P0315," "CASE Learn," "crankshaft relearn," or "crankshaft variation." GM 5.3L CASE Learn bulletins, Dodge HEMI relearn procedures, and Pentastar timing chain TSBs are all searchable here.

Should You DIY or Call a Mechanic?

DIY If You…

✓ Have a BIDIRECTIONAL scanner with relearn function
✓ Can perform a brief WOT acceleration on a safe road (GM 5.3L)
✓ Have a battery maintainer for stable voltage during procedure
✓ Are comfortable reading scanner prompts
✓ Recently had service that may have missed the relearn
✓ Want to save $100-$150 per visit on relearn services

Use a Mechanic If…

→ You don't have a bidirectional scanner (basic readers can't do this)
→ Relearn fails after multiple attempts (deeper diagnosis needed)
→ Step 5 confirms timing chain or flexplate damage
→ Multiple codes present beyond just P0315
→ European platform requiring dealer-only programming (BMW N20)
→ P0315 returns after multiple relearn attempts (unusual case)

Never authorize parts replacement for P0315 without documented relearn attempt. Required from the shop: clear documentation that they ran the manufacturer-specific relearn procedure (CASE Learn for GM, Crankshaft Variation Learn for Dodge, etc.) AND that the procedure failed to complete. If "we tried to clear it and it came back" is the entire diagnostic note, that's not adequate — demand documentation of the actual relearn attempt OR get a second opinion. A shop quoting CKP sensor + flexplate replacement on P0315 alone is committing the most common P0315 scam.

Frequently Asked Questions

Can I drive with a P0315 code?

Yes, in most cases — but address it within days, not weeks. P0315 itself doesn't damage the engine or make it unsafe to drive. The bigger concern is that P0315 disables the misfire detection system: the PCM uses the crankshaft variation data to detect misfires, and without it, real misfires from other causes (failing coils, bad injectors, low compression) won't trigger the appropriate misfire codes. You could be experiencing engine damage from undetected misfires while P0315 is active. Diagnose and fix promptly to restore full engine protection.

What's the difference between P0315 and P0335?

Both involve the crankshaft position sensor but represent very different problems. P0335 = crankshaft position sensor circuit malfunction (electrical issue — sensor failed, wiring open or shorted, no signal reaching PCM). P0315 = crankshaft position SYSTEM variation not learned (software issue — sensor signal is reaching PCM fine, but the PCM hasn't completed the relearn procedure to calibrate the unique trigger wheel pattern for this engine). P0335 needs a sensor or wiring fix. P0315 usually just needs a scanner command (relearn procedure). Both can co-occur if a sensor was replaced without performing relearn afterward.

Why do I need to perform a relearn procedure?

Every crankshaft trigger wheel has tiny manufacturing variations — the spacing between teeth isn't perfectly identical. From the factory, the PCM 'memorizes' this exact pattern as a baseline so it can use deviations from the pattern to detect misfires accurately. Three events reset this memory and require a new relearn: (1) battery disconnection — PCM loses learned values on some platforms; (2) PCM replacement or software update; (3) replacement of the CKP sensor, crankshaft, flywheel/flexplate, or timing components. Without a successful relearn, the PCM operates on default values which trigger P0315 and disable misfire detection.

How much does it cost to fix P0315?

If relearn alone fixes it (70% of cases): $0 with a bidirectional scanner DIY, or $80-$150 if a shop performs the procedure. CKP sensor replacement: $30-$80 in parts ($150-$300 at a shop with relearn included). Wiring repair: $15-$80. Timing component repair (worst case): $500-$2,000+ for timing chain or trigger wheel work. Most P0315 cases resolve under $200. The single biggest cost-saver: owning or borrowing a bidirectional scanner with relearn capability. The 5-minute software fix prevents 70% of cases from becoming expensive part-replacement chains.

What scanner do I need to fix P0315?

You need a BIDIRECTIONAL scanner that can send the manufacturer-specific crankshaft relearn command. Basic code readers and most generic scanners can only READ codes — they cannot send commands to the PCM. The iCarzone UR1000 is a 7-inch Android tablet diagnostic scanner at $499.99 with full bidirectional control, manufacturer-specific relearn procedures (GM CASE Learn, Dodge crankshaft relearn, Ford procedure, Toyota relearn), live data graphing, and broad coverage including GM 5.3L V8 trucks, Dodge Ram, Jeep, Ford F-150, BMW, and most European platforms. The relearn capability alone often saves the cost of the scanner on a single P0315 case.

Why does P0315 set after I disconnect the battery?

Some platforms — especially GM 5.3L V8 trucks and certain Dodge HEMI engines — store the crankshaft variation learned values in volatile PCM memory that resets when battery power is lost. When you reconnect the battery, the PCM has lost its calibrated reference values and immediately sets P0315 until you complete a new relearn procedure. This is why mechanics performing battery service on these platforms should always be prepared to run the relearn afterward. If you've had a recent battery service and now have P0315, this is almost certainly the cause — run the relearn first before any other diagnosis.

Can a bad timing chain cause P0315?

Yes, but it's rare. A stretched timing chain (especially common on GM 3.6L V6 LFX/LGX, Mazda SkyActiv 2.0L/2.5L, and BMW N20/N26 engines) shifts the camshaft position relative to the crankshaft by enough that the PCM can't reliably correlate the two sensor readings — preventing successful relearn. Symptoms beyond just P0315: P0008/P0009 (timing chain stretch codes), P0016/P0017 (crank-cam correlation codes), engine noise that worsens with mileage, harder cold starts. Timing chain replacement is $500-$2,000 depending on engine — not a cheap fix, but ignoring it leads to catastrophic timing failure.

Why does P0315 affect misfire detection?

Modern engines detect misfires by watching for tiny RPM drops as each cylinder fires. The PCM measures the time between trigger wheel teeth passing the crank sensor — when a cylinder fails to fire, that segment is slightly slower than the others. But this only works if the PCM knows the BASELINE timing of each tooth segment, which is what the relearn procedure stores. Without it, the PCM can't distinguish 'normal manufacturing variation' from 'misfire' — so misfire monitoring is disabled until P0315 clears. Real misfires from other problems may go undetected, allowing them to damage catalytic converters or engine internals while you remain unaware.

Written & verified by

iCarzone Tech Team Verified

Automotive Diagnostic Specialists

Our team of ASE-certified technicians and OBD-II diagnostic engineers review every article for technical accuracy. Content is based on hands-on diagnostic experience across domestic, Asian, and European vehicle platforms.

10+ years diagnostic experience ASE Certified Last reviewed: June 2026

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P0315 Code: Run the Relearn Before Buying Any Crank Sensor