Volvo All Engines (2010 Emissions) Fault Code: SPN 637 FMI 3 PID: SID 22 Crankshaft Position Sensor (CKP)

The Crank Speed Sensor is an inductive sensor that will generate a variable voltage signal when the sensor’s magnetic field is excited. When the engine is running the flywheel’s teeth rotate past the sensor’s tip and voltage pulses are generated. The Engine Control Module (ECM) monitors the frequency of the signal generated by the Crank Speed Sensor and calculates the engine RPM.

Conditions for diagnostic trouble code (DTC):
1) No signal

Observable symptoms
1) Long start time
2) Uneven operation
3) Malfunction indicator lamp (MIL) illuminated

Probable cause
1) Flywheel sensor
2) Wiring harness
3) Incorrectly installed sensor (incorrect distance to tooth wheel)
4) ECM: Engine Control Module (ECM)