| Parameter | What it measures | Common Fault | | :--- | :--- | :--- | | | Signal strength (0-5V, 0-12V, ±200V for injectors) | Voltage drop, sensor ground offset | | Frequency (Time) | Repetition rate of signal (e.g., crank sensor at idle) | Missing teeth, erratic RPM | | Duty Cycle | Ratio of on-time vs. off-time (e.g., injector pulse width) | Rich/lean condition, driver failure | | Rise/Fall Time | Speed of signal transition (nanoseconds to microseconds) | Shorted sensor, excessive capacitance in wiring |
Compare a "known good" waveform from a previous job to a "suspect" vehicle. pdf automotive oscilloscopes waveform analysis
Comparing a cam sensor against a crank sensor. | Parameter | What it measures | Common