P0315

Code

Generic P — Powertrain

Crankshaft Position System Variation Not Learned

Brand: Generic

Type: P — Powertrain

Views: UK: 36 EN: 96 RU: 71

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

PCM/ECM replaced or reprogrammed without completing crank relearn
Battery disconnected or drained, clearing learned data
Faulty crankshaft position (CKP) sensor
Faulty camshaft position (CMP) sensor
Damaged or contaminated reluctor/trigger wheel (missing/bent teeth)
Wiring/connectors open, shorted or corroded (CKP/CMP circuits)

Symptoms

DTC P0315 stored (may or may not illuminate MIL depending on manufacturer)
Hard starting or extended crank until relearn completes
Intermittent or persistent misfire, rough idle or reduced performance
Engine may stall or run poorly if timing correlation is wrong
Vehicle may fail emissions/driveability tests

What to check

Retrieve DTC(s) and freeze frame data; note any companion codes (CKP/CMP circuits, misfire, cam/crank correlation)
Check service history for recent ECM replacement, battery disconnect, or timing work
Verify battery voltage and charging during cranking (low voltage can prevent relearn)
Consult manufacturer service information for the correct crank/cam relearn procedure
Visually inspect CKP and CMP sensors, connectors, and reluctor/trigger wheel for damage, debris or missing teeth
Check for related codes (CKP/CMP circuit faults) before performing relearn

Signal parameters

CKP: periodic pulses corresponding to crankshaft speed; configuration examples include 60-2 or 58-2 reluctor patterns—missing-tooth reference gap present
CMP: one or more pulses per camshaft revolution depending on engine; used to establish cylinder identification and phase
Hall/logic sensors: digital square wave 0–5 V (keyed to battery and sensor type)
VR-type sensors: AC sine/rectified waveform; amplitude increases with RPM (typical AC at cranking 0.2–2.0 V peak-to-peak, higher at higher RPM)
Correlation: CKP-to-CMP phase must fall within manufacturer-specified degrees; deviation indicates timing or sensor alignment problem
During cranking the number/frequency of pulses should match tooth count × crank revs; missing or extra pulses indicate reluctor or sensor faults

Diagnostic algorithm

Confirm P0315 is current; record freeze frame and any related DTCs (CKP/CMP, misfire, cam/crank correlation codes).
Check service history for recent ECM replacement, battery disconnect, or timing component work. If relearn was not done, perform the manufacturer-specified crank/cam variation relearn procedure using a capable scan tool. Clear codes and retest.
If relearn succeeds and code does not return, report complete. If relearn fails or cannot complete, continue diagnostics.
Verify battery state and charging (>= 11.5–12 V during crank recommended); poor voltage can prevent relearn. Repair charging/battery issues before proceeding.
Visually inspect CKP and CMP sensors, connectors and reluctor/trigger wheel for damage, contamination, missing/bent teeth, or loose mounting. Repair or replace as needed.
Check CKP/CMP wiring harness continuity and resistance; check for shorts to power/ground and intermittent connector faults (wiggle test).
Capture simultaneous CKP and CMP waveforms with an oscilloscope while cranking and at idle. Look for missing pulses, irregular amplitude, noise, or incorrect phase relationship. Compare to manufacturer waveform examples and phase spec.
If waveforms show sensor/electrical issues, repair or replace the defective sensor or wiring and repeat relearn. After repairs, clear codes and perform relearn again.
If waveforms look correct electrically but phase is out of spec, inspect mechanical timing (timing belt/chain condition, timing marks, cam/crank sprocket alignment). Repair any mechanical timing faults and repeat relearn.
If all sensors, wiring, and mechanical timing are good and relearn still fails, consider PCM calibration/software or PCM hardware fault. Verify correct PCM part number and programming; replace/reprogram PCM per manufacturer instructions and perform relearn afterward.

Likely causes

Recent ECM replacement, battery disconnect or service that clears learned values (most likely)
Incomplete or failed crank/cam relearn procedure
Failed or marginal CKP sensor or CMP sensor
Damaged reluctor (missing/bent teeth) or foreign debris on reluctor
Wiring harness or connector fault to CKP/CMP sensors
Mechanical timing jumped (belt/chain) or incorrect timing after service

Fault status

⚠️ Status

PCM/ECM has not learned the crankshaft position system variation (CKP-to-CMP correlation). Relearn/calibration required or sensor/wiring/timing fault preventing learn.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours