External Safety Path

The M73 engine continues to use an EML system for throttle control. The External safety path input is connected between the DME control modules and the accelerator pedal. If the DME receives a high signal on the safety path input, the decel fuel cut off function is activated. This safety feature ensures that the DME control modules will not allow engine RPM to exceed idle if the EML system malfunctions.

The external safety path exists from the brake light switch through the pedal position sensor 40 switch to the DME control modules. If the accelerator pedal is released, the 40 switch closes. If the engine does not return to idle, stepping on the brake will apply a high signal through the 40 switch to the DME control modules. With this signal, decel fuel cut off is activated.