diff --git a/opendbc_repo/opendbc/car/hyundai/carcontroller.py b/opendbc_repo/opendbc/car/hyundai/carcontroller.py
index 0f0485fa1..ed2ef129d 100644
--- a/opendbc_repo/opendbc/car/hyundai/carcontroller.py
+++ b/opendbc_repo/opendbc/car/hyundai/carcontroller.py
@@ -583,6 +583,11 @@ class CarController(CarControllerBase):
     if self.long_active_ecu:
       if lka_steering:
         can_sends.extend(hyundaicanfd.create_adrv_messages(self.packer, self.CAN, self.frame))
+        # Ioniq 6: front radar treats ADAS_DRV's 0x100 broadcast as its host heartbeat
+        # and stops publishing object tracks when it disappears. Spoof it at 100 Hz on
+        # PT bus so the radar keeps tracking.
+        if self.CP.carFingerprint == CAR.HYUNDAI_IONIQ_6:
+          can_sends.append(hyundaicanfd.create_accelerator_brake_alt_spoof(0, self.frame, CS.out.brakePressed, CS.out.gasPressed))
       elif not ccnc_non_hda2:
         can_sends.extend(hyundaicanfd.create_fca_warning_light(self.packer, self.CAN, self.frame))
       if self.CP.carFingerprint == CAR.HYUNDAI_IONIQ_6 and self.frame % 5 == 0:
diff --git a/opendbc_repo/opendbc/car/hyundai/hyundaicanfd.py b/opendbc_repo/opendbc/car/hyundai/hyundaicanfd.py
index 48c84c6ba..396e311f2 100644
--- a/opendbc_repo/opendbc/car/hyundai/hyundaicanfd.py
+++ b/opendbc_repo/opendbc/car/hyundai/hyundaicanfd.py
@@ -702,3 +702,22 @@ def hkg_can_fd_checksum(address: int, sig, d: bytearray) -> int:
   elif len(d) == 32:
     crc ^= 0x9F5B
   return crc
+
+
+# Ioniq 6 / HKG LKA-steering: ADAS_DRV broadcasts ACCELERATOR_BRAKE_ALT (0x100) at 100 Hz on bus 0.
+# The front radar uses this as its "host alive" heartbeat. When we disable ADAS_DRV the
+# radar stops publishing real object tracks. Spoof this message ourselves with valid CRC
+# and current pedal state so the radar keeps tracking.
+# Length is 24 bytes on Ioniq 6 (DBC declares 32 for ICE Hyundais, but EV firmware uses 24).
+# Byte template captured from a real ADAS broadcast; bytes 6-23 appear static / config.
+_ACCEL_BRAKE_ALT_TEMPLATE = bytes.fromhex("000000020000fcff000000000020000055ff000068000000")
+
+def create_accelerator_brake_alt_spoof(bus: int, counter: int, brake_pressed: bool, accelerator_pressed: bool) -> CanData:
+  d = bytearray(_ACCEL_BRAKE_ALT_TEMPLATE)
+  d[2] = counter & 0xFF                              # COUNTER (bit 16, 8-bit)
+  d[4] = (d[4] & ~0x01) | (0x01 if brake_pressed else 0x00)         # BRAKE_PRESSED (bit 32)
+  d[22] = (d[22] & ~0x01) | (0x01 if accelerator_pressed else 0x00) # ACCELERATOR_PEDAL_PRESSED (bit 176)
+  crc = hkg_can_fd_checksum(0x100, None, d)
+  d[0] = crc & 0xFF
+  d[1] = (crc >> 8) & 0xFF
+  return CanData(0x100, bytes(d), bus)
diff --git a/opendbc_repo/opendbc/safety/modes/hyundai_canfd.h b/opendbc_repo/opendbc/safety/modes/hyundai_canfd.h
index 063f9de8f..2341191bf 100644
--- a/opendbc_repo/opendbc/safety/modes/hyundai_canfd.h
+++ b/opendbc_repo/opendbc/safety/modes/hyundai_canfd.h
@@ -306,6 +306,7 @@ static safety_config hyundai_canfd_init(uint16_t param) {
     HYUNDAI_CANFD_SCC_CONTROL_COMMON_TX_MSGS(1, true)
     HYUNDAI_CANFD_BLINDSPOT_DASH_TX_MSGS(1)
     {0x51,  0, 32, .check_relay = false},  // ADRV_0x51
+    {0x100, 0, 24, .check_relay = false},  // Ioniq 6: ACCELERATOR_BRAKE_ALT radar heartbeat spoof
     {0x730, 1,  8, .check_relay = false},  // tester present for ADAS ECU disable
     {0x160, 1, 16, .check_relay = false},  // ADRV_0x160
     {0x1EA, 1, 32, .check_relay = false},  // ADRV_0x1ea