A Crankshaft Position Sensor (CKPS) is a magnetic type sensor that generates voltage using a sensor and a target wheel mounted on the crankshaft; there are 58 slots in the target wheel where one is longer than the others. When the slot in the wheel aligns with the sensor, the sensor voltage outputs low. When the metal (tooth) in the wheel aligns with the sensor, the sensor voltage outputs high. During one crankshaft rotation there are 58 rectangular signals and one longer signal. The ECM calculates engine RPM by using the sensor’ s signal and controls the injection duration and the ignition timing. Using the signal differences caused by the longer slot, the ECM identifies which cylinder is at top dead center.
If signal input phase is abnormal, ECM sets DTC P0340.
Item
Detecting Condition
Possible Cause
DTC Strategy
Sensor wrong mounted (check the assembling state)
Poor connection
abnormal assembling state
CMPS
Enable Conditions
The count of Phase edges detection > 8 times
Threshold Value
Abnormal phase edges (High or Low)
Diagnostic Time
-
MIL ON Condition
3 driving cycle
This example shows a typical Crankshaft Position Sensor(CkPS) and Camshaft Position Sensor(CMPS) waveform at idle. The ECM controls the injection and ignition timing by using these signals. Generally CkPS signal is used to detect the piston’s position and CMPS signal is used to detect the Top Dead Center of each cylinder.