Camshaft Position Sensor
2021 Honda Civic · 1.5L I4 Turbo
Sensor Type
hall-effect
Waveform Type
dc-square
Location
Mounted on the rear of the cylinder head near the timing chain cover, monitoring the intake camshaft reluctor wheel
Pins
3-pin connector
Idle Frequency
16.5 Hz
Timebase
50ms/div
Voltage Scale
2V/div
Trigger
2.5V, rising edge
Wiring
Blue wire (signal), Green/White wire (ground), Black/Yellow wire (5V reference)
Expected Voltage Range
At Idle
0.2V to 4.8V
At Higher RPM
0.2V to 4.8V
Expected Pattern
6 pulses per camshaft revolution with one identifying pulse of different width for synchronization, pattern repeats every 720 degrees of crankshaft rotation
Known-Good Waveform
Digital square wave signal showing 6 distinct pulses per cam revolution with one reference pulse that is narrower than the others for ECM synchronization. Signal should transition cleanly between 0.3V and 4.7V with frequency of approximately 16.5 Hz at idle. The pattern should align predictably with crankshaft position sensor at a 2:1 ratio.
Common Failure Patterns
Missing pulses or inconsistent pulse pattern, particularly the reference pulse
Cause: Timing chain stretch causing erratic cam-to-crank correlation or sensor contamination from VTEC solenoid oil spray
Diagnostic Tips
The 1.5T engine is known for timing chain stretch issues especially after 100k miles. Always compare cam-to-crank correlation (P0016/P0017) when diagnosing CMP issues. Check VTEC oil pressure control solenoid for leaks that can contaminate the sensor connector.
Related Diagnostic Trouble Codes
P0340P0341P0342P0343P0344
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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