Cars · Electronics
Crankshaft Position Sensor
The crank position (CKP) sensor and how the ECU uses it.
The crankshaft position (CKP) sensor tells the ECU how fast the engine is turning and where it is in its rotation. The ECU uses that signal as the timing reference for both fuel injection and ignition, so without a good CKP signal the engine will not run.
On many older Hondas the crank, cylinder (CYP) and top-dead-centre (TDC) sensors are housed together inside the distributor, reading toothed reluctor wheels turned by the camshaft. The CKP wheel carries many teeth for fine resolution of engine speed, while the TDC and CYP wheels use fewer teeth to mark specific cylinder positions.