diff --git a/opendbc_repo/opendbc/car/tesla/preap/carstate.py b/opendbc_repo/opendbc/car/tesla/preap/carstate.py
index 377339494..78cd2fedc 100644
--- a/opendbc_repo/opendbc/car/tesla/preap/carstate.py
+++ b/opendbc_repo/opendbc/car/tesla/preap/carstate.py
@@ -49,6 +49,10 @@ def update_preap(cs, can_parsers):
   ))
   cs.engagement.handle_steering_disengage(ret.steeringDisengage)
 
+  gtw_epas = cp_chassis.vl["GTW_epasControl"]
+  # Pre-AP steering requires the EPAS firmware patch to advertise angle control and LDW enabled.
+  ret.invalidLkasSetting = (gtw_epas["GTW_epasControlType"] != 1) or (gtw_epas["GTW_epasLDWEnabled"] != 1)
+
   cruise_state = cs.can_define.dv["DI_state"]["DI_cruiseState"].get(int(cp_chassis.vl["DI_state"]["DI_cruiseState"]), None)
   cs.di_cruise_state = cruise_state or "OFF"
   speed_units = cs.can_define.dv["DI_state"]["DI_speedUnits"].get(int(cp_chassis.vl["DI_state"]["DI_speedUnits"]), None)
@@ -116,7 +120,7 @@ def update_preap(cs, can_parsers):
 def get_preap_can_parsers(CP):
   chassis_messages = [
     ("ESP_B", 0), ("BrakeMessage", 0), ("DI_state", 0), ("DI_torque2", 0),
-    ("GTW_carState", 0), ("STW_ANGLHP_STAT", 0), ("EPAS_sysStatus", 0), ("STW_ACTN_RQ", 0),
+    ("GTW_carState", 0), ("GTW_epasControl", 0), ("STW_ANGLHP_STAT", 0), ("EPAS_sysStatus", 0), ("STW_ACTN_RQ", 0),
   ]
   pt_messages = [("DI_torque1", 0)]
   pedal_messages = [("GAS_SENSOR", 50)] if nap_conf.use_pedal else []
@@ -126,4 +130,3 @@ def get_preap_can_parsers(CP):
     Bus.pt: CANParser(DBC[CP.carFingerprint][Bus.pt], pt_messages, CANBUS.party),
     Bus.chassis: CANParser(DBC[CP.carFingerprint][Bus.chassis], chassis_messages, CANBUS.party),
   }
-
diff --git a/selfdrive/selfdrived/events.py b/selfdrive/selfdrived/events.py
index 8c4a387ad..ee4347df8 100644
--- a/selfdrive/selfdrived/events.py
+++ b/selfdrive/selfdrived/events.py
@@ -402,6 +402,8 @@ def personality_changed_alert(CP: car.CarParams, CS: car.CarState, sm: messaging
 
 def invalid_lkas_setting_alert(CP: car.CarParams, CS: car.CarState, sm: messaging.SubMaster, metric: bool, soft_disable_time: int, personality, starpilot_toggles: SimpleNamespace) -> Alert:
   text = "Toggle stock LKAS on or off to engage"
+  if CP.brand == "tesla" and CP.carFingerprint == "TESLA_MODEL_S_PREAP":
+    return NormalPermanentAlert("EPAS Firmware Required", "Flash Pre-AP EPAS firmware to enable steering")
   if CP.brand == "tesla":
     text = "Switch to Traffic-Aware Cruise Control to engage"
   elif CP.brand == "mazda":