3-8 ENGINE CONTROL SYSTEM
SENSOR AND SWITCH
CKP (Crankshaft Position) SENSOR
The CKP sensor which is a “Hall effect sensor” type is installed
below the flywheel rotor. When the reluctor bars on the flywheel
passes the sensor, signals are generated and rectified to create
“ON” (high voltage) and “OFF” (low voltage) signals in the sen-
sor. These signals are sent to the ECM and are the fundamental
signals used to judge the engine speed and crankshaft angle.
There are 34 reluctor bars, spaced 10 degrees apart, followed
by a larger index space. During one crankshaft rotation, 34 sig-
nals are supplied from the CKP sensor to the ECM.
CMP (Camshaft Position) SENSOR
The CMP sensor is installed on the side of the camshaft pulley.
When the reluctor bars (trigger vanes) on the camshaft pulley
passes the sensor, signals (voltage pulses) are generated and
sent to the ECM.
There are four trigger vanes on the camshaft pulley. During one
rotation of the camshaft (two rotations of the crankshaft), four
signals are supplied from the CMP sensor to the ECM.
ECM cylinder identification:
The cylinder is identified by a calculation combined from two
signals; one from the CKP sensor and one from the CMP sen-
sor.
10˚
120˚
120˚
120˚
4-signals/720˚
34-signals/360˚
CKP sensor
signal
CMP sensor
signal
30˚