Powertrain, generic · Ignition system or misfire

P0315 Crankshaft Position System Variation Not Learned

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Manufacturing tolerances of the crankshaft tone wheel distort the speed fluctuations misfire detection relies on, so the engine module learns a correction for each tooth or segment. P0315 means these values have not been learned or are invalid. GM checks that the learned tooth angles add up to 360° (deviation above 0.001° sets the code in the first trip) and learns them with a scan tool: brakes held, full throttle in park until fuel cut-off. Ford learns the profile during up to three overrun phases from 60 to 40 mph and sets P0315 when that fails. Until relearned, misfire detection is suspended – at GM above 1,000 rpm – and misfire readiness stays incomplete. The relearn is needed after replacing the engine, engine module, crankshaft, damper or crankshaft sensor.

Likely causes

Relearn not performed after replacing sensor, crankshaft, damper, engine or engine module
Learned values lost through voltage loss (battery disconnected)
Tone wheel damaged or shifted, crankshaft runout, dirt on the sensor
Interference in the crankshaft sensor circuit
Engine module memory faulty

Symptoms

  • Check engine light on (GM; Ford depending on application)
  • Driving usually unaffected
  • Misfire readiness not set – emissions test fails

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–200
Time0.3–1 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

crankshaft position sensorcrankshaft tone wheelengine control module

Related codes

P0300P0335P0336P0316P0313

References: gsi.ext.gm.com, saabwisonline.com, saabwisonline.com, fordservicecontent.com.