SW2 L4-1.9L DOHC VIN 7 (1997)
Crankshaft Position Sensor: Description and Operation
The PCM receives signals from the crankshaft position sensor to determine the position of the engine at various degrees of rotation.
The EI module does not receive a signal from the crankshaft position (CKP) sensor. Instead the CPK sensor signal is being received and processed by
the PCM. The EI module does, however, contain circuitry to determine camshaft position without using a camshaft sensor, by use of compression sense
ignition (CSI). The CSI circuitry makes use of the characteristics of a waste spark ignition system, while monitoring a sequence of spark plug gap
breakdown events. Capacitive pickup plates located under the 1/4 coil are used to determine whether #1 or #4 fired on a compression stroke. This
capacitive sensing device is similar to inductive pickups used on engine analyzers and oscilloscopes.