The clutch switch tells the ECU when the pedal is pressed. On a Nexus it's used to arm launch control, to help with gear detection alongside a gear switch, and as a logged channel that makes shift points and launches easy to spot when you review data.
Input mode
Under Options, set Clutch Switch Input Mode to either a digital switched input wired to the ECU, or the vehicle CAN bus if the car already reports clutch position over CAN. When you use a digital input, the Connections node lets you pick any free AVI or SPI.
AVI or SPI settings
| Input | Setting | What to set |
|---|---|---|
| AVI | Switch On Voltage / Switch Off Voltage | The voltages where the ECU decides the switch has changed state. Leave a gap between them so noise can't toggle the input. For a switch that pulls a 5V signal to ground when pressed, On around 1V and Off around 4V works well. |
| SPI | Edge Select | Falling if the switch grounds the input when pressed, Rising if it supplies voltage when pressed |
| SPI | Sensor Type | Hall Effect for any switch input |
| SPI | Pull Up | On for a switch that only grounds the input, so the ECU sees a clean high when it's released |
Arming voltage and glitch filter
If you use an SPI, two extra tables appear. The Arming Voltage table is only active when the SPI's signal type is set to Reluctor. It sets the voltage the signal must reach before the ECU starts watching for the activation edge. With a plain switch set to Hall Effect you normally won't need it.
The Glitch Filter sets how long, in microseconds, the signal has to stay in its new state before the ECU accepts the change. Anything shorter is thrown away as noise. That's useful on switches that bounce as their contacts close. For the theory behind both tables, see arming voltage and glitch filter.
Watch the clutch channel live while someone presses and releases the pedal slowly. It should switch once each way, at a sensible point in the pedal travel, with no flicker.
On an Elite? See clutch switch on the Elite.
