diff --git a/selfdrive/car/gm/carstate.py b/selfdrive/car/gm/carstate.py
index 8958c5513..d26f75c5d 100644
--- a/selfdrive/car/gm/carstate.py
+++ b/selfdrive/car/gm/carstate.py
@@ -101,7 +101,11 @@ class CarState(CarStateBase):
 
     no_accel_pos = bool(self.CP.flags & GMFlags.NO_ACCELERATOR_POS_MSG.value)
 
-    if no_accel_pos:
+    # Hardcode Volt ASCM to the 0xBE brake source; no fallback path.
+    if self.CP.carFingerprint == CAR.CHEVROLET_VOLT_ASCM:
+      no_accel_pos = False
+      ret.brake = pt_cp.vl["EBCMBrakePedalPosition"]["BrakePedalPosition"]
+    elif no_accel_pos:
       if self.CP.carFingerprint in kaofui_state_cars:
         ret.brake = pt_cp.vl.get("EBCMBrakePedalPosition", {}).get("BrakePedalPosition", 0) / 0xd0
       else: