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 cylinderCrank shaft position is closely related to engine starting.
P0340 is set when CMPS is not detected while CKPS signal is sensed. This code is due to CMPS circuit problem or component failure.
Item
Detecting Condition
Possible Cause
Threshold Value
? CMPS signal is not detected.
? CMPS circuit
? CMPS component
? Too wide air gap
Fail Safe
? Failure occurs at cranking : fuel injection stops(engine ON is impossible)
? Failure occurs at engine running : using cylinder data before failure happens. Engine running is possible only untill engine OFF.
Check Lamp
NO
? CMPS Signal Waveform Analysis
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.
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.