Main Relay Control
Configure the logical Output and Output mode under Controller > Actuator Outputs > Main relay output. The physical pin and its drive capability come from the installed board, not from the configuration label.
Main-relay behavior is also a firmware-build feature. The base STM32F4 feature
default is EFI_MAIN_RELAY_CONTROL = FALSE; board targets may enable it. On
builds with control disabled, the output is held on except during a relay bench
test. Do not assume battery-voltage-driven shutoff is active on every board.
Behavior when enabled
Capoworks treats battery voltage above 5 V as ignition voltage. While that voltage is present, the relay is requested on. After it disappears, the main relay controller and other engine modules can request delayed shutoff; the controller's own holdover is one second after the last valid ignition-voltage sample. The output remains on for a bench request, ignition voltage, or any module's delayed-shutoff request.
If a Main Relay Voltage sensor is configured, the relay output begins on and the controller waits 0.5 seconds before comparing measured battery and main-relay voltages. A difference greater than 3 V raises the main-relay fault warning. Verify that the sensor represents the intended post-relay supply; otherwise a correct relay can still report a fault.
The Main Relay bench command holds a bench request for about one second, then normal logic evaluates again. Observe the physical relay and the Main relay: On channel. If the channel changes but the relay does not, check the board output circuit and relay supply. If neither changes, check pin, output mode, battery-voltage input, and whether this firmware build includes main-relay control.