diff --git a/selfdrive/modeld/constants.py b/selfdrive/modeld/constants.py
index a5ac977390..e03d93d7e8 100644
--- a/selfdrive/modeld/constants.py
+++ b/selfdrive/modeld/constants.py
@@ -25,6 +25,8 @@ class ModelConstants:
   # model outputs constants
   FCW_THRESHOLDS_5MS2 = np.array([.05, .05, .15, .15, .15], dtype=np.float32)
   FCW_THRESHOLDS_3MS2 = np.array([.7, .7], dtype=np.float32)
+  FCW_5MS2_PROBS_WIDTH = 5
+  FCW_3MS2_PROBS_WIDTH = 2
 
   DISENGAGE_WIDTH = 5
   POSE_WIDTH = 6
diff --git a/selfdrive/modeld/fill_model_msg.py b/selfdrive/modeld/fill_model_msg.py
index 05a159c86d..55d7abc1aa 100644
--- a/selfdrive/modeld/fill_model_msg.py
+++ b/selfdrive/modeld/fill_model_msg.py
@@ -12,8 +12,8 @@ ConfidenceClass = log.ModelDataV2.ConfidenceClass
 class PublishState:
   def __init__(self):
     self.disengage_buffer = np.zeros(ModelConstants.CONFIDENCE_BUFFER_LEN*ModelConstants.DISENGAGE_WIDTH, dtype=np.float32)
-    self.prev_brake_5ms2_probs = np.zeros(ModelConstants.DISENGAGE_WIDTH, dtype=np.float32)
-    self.prev_brake_3ms2_probs = np.zeros(ModelConstants.DISENGAGE_WIDTH, dtype=np.float32)
+    self.prev_brake_5ms2_probs = np.zeros(ModelConstants.FCW_5MS2_PROBS_WIDTH, dtype=np.float32)
+    self.prev_brake_3ms2_probs = np.zeros(ModelConstants.FCW_3MS2_PROBS_WIDTH, dtype=np.float32)
 
 def fill_xyzt(builder, t, x, y, z, x_std=None, y_std=None, z_std=None):
   builder.t = t