The Camshaft Position Sensor (CMPS) is a sensor that detects the compression TDC of the NO. 1 cylinder. The CMPS consists of a hall type sensor and a target on the end of the intake camshaft. When the target triggers the sensor, the sensor voltage is 5V. If not, the sensor voltage is 0V. These CMPS signal is sent to the PCM and the PCM uses the CMPS signal for synchronizing the firing of sequential fuel injectors.
Checking oputput signals from CMP during engine running, if the expected number of cam tooth count is not. observed, PCM sets P0341. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item
Detecting Condition
Possible cause
DTC Strategy
? Check if CAM sensor is synchronized correctly
? Poor connection
? Short in harness
? Electrical noise
? Target wheel
? CMPS
? PCM
Enable Conditions
? Engine running state
Threshold value
? Cam tooth count ? 6
Diagnosis Time
? Continuous
MIL On Condition
? 2 driving cycles
Fig) Signal waveform of CKPS and CMPS at idle
This example shows a typical Crankshaft Position Sensor(CKPS) and Camshaft Position Sensor(CMPS) waveform at idle. The PCM 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.