diff --git a/Marlin/src/HAL/TEENSY40_41/inc/SanityCheck.h b/Marlin/src/HAL/TEENSY40_41/inc/SanityCheck.h
index ae8fe9b69eda..7b1c466f2338 100644
--- a/Marlin/src/HAL/TEENSY40_41/inc/SanityCheck.h
+++ b/Marlin/src/HAL/TEENSY40_41/inc/SanityCheck.h
@@ -48,3 +48,11 @@
 #if ENABLED(BAUD_RATE_GCODE) && SERIAL_PORT_2 == -2
   #error "BAUD_RATE_GCODE cannot be enabled when using the Ethernet serial port."
 #endif
+
+#if ENABLED(SPINDLE_LASER_USE_PWM) && !ENABLED(SILENCE_TEENSY_SPINDLE_LASER_WARNING)
+  #warning "SPINDLE_LASER_USE_PWM is untested on Teensy 4.0/4.1, see https://www.pjrc.com/teensy/td_pulse.html for details on frequencies, and resolution. #define SILENCE_TEENSY_SPINDLE_LASER_WARNING to silence warning."
+#endif
+
+#if ENABLED(FAST_PWM_FAN) && FAST_PWM_FAN_FREQUENCY == 1000U
+  #warning "FAST_PWM_FAN_FREQUENCY has been left as default, see https://www.pjrc.com/teensy/td_pulse.html and consider raising it to reduce noise."
+#endif