diff --git a/klippy/extras/tmc.py b/klippy/extras/tmc.py
index 55ccdfb4..ba1bc41c 100644
--- a/klippy/extras/tmc.py
+++ b/klippy/extras/tmc.py
@@ -437,7 +437,7 @@ class TMCVirtualPinHelper:
             self.diag_pin_field = None
         self.mcu_endstop = None
         self.en_pwm = False
-        self.pwmthrs = 0
+        self.pwmthrs = self.coolthrs = 0
         # Register virtual_endstop pin
         name_parts = config.get_name().split()
         ppins = self.printer.lookup_object("pins")