Cam Shaft Position Sensor(CMPS) is hall sensor type. Sensing the teeth attatch at the end of exhaust cam shaft, CMPS detects rotation of Cam shaft (1 signal per 1 lotation).
As Cam shaft rotates once while Crank shaft does twice, CMPS referrence point generates once while CKPS' do twice.
As this signal inputted to ECM, it distinguishes crank angle and the cylinder which requires fuel injection in order to determine injection sequence and duration.
P0341 is set when CMPS reference point is detected more or less than twice while CKPS reference point is recognized 4 times. This code is due to temporary poor connection or short to ground in CMPS circuit. CMPS component failure.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal monitoring
CMPS circuit
CMPS component
Enable Conditions
Engine running(during accelerating)
Threshold Value
When the signal from CMPS is abnormal.
Diagnostic Time
-
Fail Safe
Fuel cut
YES
EGR Off
Fuel Limit
NO
MIL
Sensor Type
Output Signal
Characteristic
Air Gab
LOW Signal
Detecting Voltage
HIGH Signal
Hall effect type
0V~5V Digital
signal output
1.25mm
below 2.0V
above 3.8V
Fig.1) This shows waveform of Crank Shaft Position Sensor and Cam Shaft Position Sensor simulatneously. The middle area indicates reference points of Crank Shaft Position Sensor and Cam Shaft Position Sensor.
Fig.2) Crank Shaft Position Sensor and Cam Shaft Position Sensor signal are measured simultaneously. Cam Shaft Position Sensor signal is outputted once when Crank Shaft Position sensor signal is outputted twice. LOW and HIGH output of Cam Shaft Position sensor reference point is detected at Crank Shaft Position sensor reference point. ( Injection sequence is determined based on LOW and HIGH signal of Cam Shaft Position Sensor reference point as detecting cylinder position.)
? Signal Analysis
1) ECM recognizes HIGH signal as LOW signal when CMPS signal drops below 2.0V and LOW signal as HIGH signal
when CMPS signal rises above 3.8V.
2) V0 - the Minimum voltage of LOW signal does not drop below 0.0V due to the hall sensor inside resistance. When the Minimum voltage of LOW signal is above 0.6V during signal waveform inspection, check excessive resistance inside of CMPS component or in ground circuit.