What it does
Every crank or cam tooth the ECU sees is a voltage changing on the trigger input. The Trigger Activation Voltage is the point that signal must pass through for the Nexus to accept it as a real trigger event and act on it. Pick the right point and the ECU sees each tooth cleanly; pick a poor one and it can miss teeth or count noise as extra teeth.
It works together with the trigger arming threshold voltage, which the signal must reach first before the ECU is ready to look for the activation point. That two-step approach is what keeps small wobbles in the signal from being counted.
When you can edit it
The table is only active when the trigger Sensor Type is set to Custom. For the standard sensor types, NSP locks it to a fixed value:
| Sensor type | Activation voltage |
|---|---|
| Reluctor | Fixed at 0.0V. A reluctor produces an AC signal, and the zero crossing is the most accurate point to time from |
| Hall Effect, falling edge | Fixed at 2.0V |
| Hall Effect, rising edge | Fixed at 3.0V |
| Custom | Set by you in this table |
When to use Custom
We only reach for Custom when a sensor's signal doesn't behave like a textbook reluctor or Hall sensor, and we always look at the waveform first with the Haltech ECU oscilloscope or a scope. Guessing at trigger voltages without seeing the signal is how you end up with an engine that starts but misfires or loses sync at high rpm. If a trigger problem looks like noise rather than a threshold issue, check the trigger glitch filter and your wiring before changing thresholds. More on the full setup is in our trigger system article.
