diff --git a/opendbc/car/docs_definitions.py b/opendbc/car/docs_definitions.py
index db022f9143..5e0fa28a00 100644
--- a/opendbc/car/docs_definitions.py
+++ b/opendbc/car/docs_definitions.py
@@ -114,6 +114,8 @@ class CarHarness(EnumBase):
   custom = BaseCarHarness("Developer connector")
   obd_ii = BaseCarHarness("OBD-II connector", parts=[Cable.long_obdc_cable, Cable.long_obdc_cable], has_connector=False)
   gm = BaseCarHarness("GM connector", parts=[Accessory.harness_box])
+  gmsdgm = BaseCarHarness("GM SDGM connector", parts=[Accessory.harness_box, Cable.rj45_cable_7ft, Cable.long_obdc_cable,
+                                                      Cable.usbc_coupler, Accessory.comma_power_v2])
   nissan_a = BaseCarHarness("Nissan A connector", parts=[Accessory.harness_box, Cable.rj45_cable_7ft, Cable.long_obdc_cable, Cable.usbc_coupler])
   nissan_b = BaseCarHarness("Nissan B connector", parts=[Accessory.harness_box, Cable.rj45_cable_7ft, Cable.long_obdc_cable, Cable.usbc_coupler])
   mazda = BaseCarHarness("Mazda connector")
diff --git a/opendbc/car/gm/carstate.py b/opendbc/car/gm/carstate.py
index cd30639787..318646bbe2 100644
--- a/opendbc/car/gm/carstate.py
+++ b/opendbc/car/gm/carstate.py
@@ -5,7 +5,7 @@
 from opendbc.car.common.conversions import Conversions as CV
 from opendbc.car.common.numpy_fast import mean
 from opendbc.car.interfaces import CarStateBase
-from opendbc.car.gm.values import DBC, AccState, CanBus, CruiseButtons, STEER_THRESHOLD
+from opendbc.car.gm.values import DBC, AccState, CanBus, CruiseButtons, STEER_THRESHOLD, SDGM_CAR
 
 ButtonType = structs.CarState.ButtonEvent.Type
 TransmissionType = structs.CarParams.TransmissionType
@@ -119,7 +119,8 @@ def update(self, pt_cp, cam_cp, _, __, loopback_cp) -> structs.CarState:
     ret.cruiseState.standstill = pt_cp.vl["AcceleratorPedal2"]["CruiseState"] == AccState.STANDSTILL
     if self.CP.networkLocation == NetworkLocation.fwdCamera:
       ret.cruiseState.speed = cam_cp.vl["ASCMActiveCruiseControlStatus"]["ACCSpeedSetpoint"] * CV.KPH_TO_MS
-      ret.stockAeb = cam_cp.vl["AEBCmd"]["AEBCmdActive"] != 0
+      if self.CP.carFingerprint not in SDGM_CAR:
+        ret.stockAeb = cam_cp.vl["AEBCmd"]["AEBCmdActive"] != 0
       # openpilot controls nonAdaptive when not pcmCruise
       if self.CP.pcmCruise:
         ret.cruiseState.nonAdaptive = cam_cp.vl["ASCMActiveCruiseControlStatus"]["ACCCruiseState"] not in (2, 3)
@@ -144,10 +145,13 @@ def get_cam_can_parser(CP):
     messages = []
     if CP.networkLocation == NetworkLocation.fwdCamera:
       messages += [
-        ("AEBCmd", 10),
         ("ASCMLKASteeringCmd", 10),
         ("ASCMActiveCruiseControlStatus", 25),
       ]
+      if CP.carFingerprint not in SDGM_CAR:
+        messages += [
+          ("AEBCmd", 10),
+        ]
 
     return CANParser(DBC[CP.carFingerprint]["pt"], messages, CanBus.CAMERA)
 
diff --git a/opendbc/car/gm/fingerprints.py b/opendbc/car/gm/fingerprints.py
index 57dbff41b6..971e83eb3d 100644
--- a/opendbc/car/gm/fingerprints.py
+++ b/opendbc/car/gm/fingerprints.py
@@ -57,6 +57,10 @@
   {
     190: 6, 201: 8, 211: 2, 717: 5, 241: 6, 451: 8, 298: 8, 452: 8, 453: 6, 479: 3, 485: 8, 249: 8, 500: 6, 587: 8, 1611: 8, 289: 8, 481: 7, 193: 8, 197: 8, 209: 7, 455: 7, 489: 8, 309: 8, 413: 8, 501: 8, 608: 8, 609: 6, 610: 6, 611: 6, 612: 8, 613: 8, 311: 8, 510: 8, 528: 5, 532: 6, 715: 8, 560: 8, 562: 8, 707: 8, 789: 5, 869: 4, 880: 6, 761: 7, 840: 5, 842: 5, 844: 8, 313: 8, 381: 8, 386: 8, 810: 8, 322: 7, 384: 4, 800: 6, 1033: 7, 1034: 7, 1296: 4, 753: 5, 388: 8, 288: 5, 497: 8, 463: 3, 304: 3, 977: 8, 1001: 8, 1280: 4, 320: 4, 352: 5, 563: 5, 565: 5, 1221: 5, 1011: 6, 1017: 8, 1020: 8, 1249: 8, 1300: 8, 328: 1, 1217: 8, 1233: 8, 1259: 8, 1261: 7, 1263: 4, 1265: 8, 1267: 1, 1930: 7, 1271: 8
   }],
+  CAR.CADILLAC_XT4: [
+  {
+    190: 6, 193: 8, 197: 8, 199: 4, 201: 8, 209: 7, 211: 2, 241: 6, 249: 8, 257: 8, 288: 5, 289: 8, 292: 2, 298: 8, 304: 3, 309: 8, 313: 8, 320: 4, 322: 7, 328: 1, 331: 3, 352: 5, 353: 3, 368: 3, 381: 8, 384: 4, 386: 8, 388: 8, 393: 7, 398: 8, 401: 8, 407: 7, 413: 8, 417: 7, 419: 1, 422: 4, 426: 7, 431: 8, 442: 8, 451: 8, 452: 8, 453: 6, 455: 7, 479: 3, 481: 7, 485: 8, 489: 8, 497: 8, 499: 3, 500: 6, 501: 8, 503: 2, 508: 8, 532: 6, 554: 3, 560: 8, 562: 8, 563: 5, 564: 5, 565: 5, 567: 5, 573: 1, 577: 8, 608: 8, 609: 6, 610: 6, 611: 6, 612: 8, 613: 8, 647: 6, 707: 8, 715: 8, 717: 5, 719: 5, 761: 7, 806: 1, 840: 5, 842: 5, 844: 8, 866: 4, 869: 4, 872: 1, 880: 6, 961: 8, 969: 8, 975: 2, 977: 8, 979: 8, 985: 5, 1001: 8, 1005: 6, 1009: 8, 1011: 6, 1013: 5, 1017: 8, 1020: 8, 1033: 7, 1034: 7, 1037: 5, 1105: 5, 1187: 5, 1195: 3, 1217: 8, 1221: 5, 1223: 2, 1225: 7, 1233: 8, 1236: 8, 1249: 8, 1257: 6, 1259: 8, 1261: 7, 1263: 4, 1265: 8, 1267: 1, 1268: 2, 1271: 8, 1273: 3, 1276: 2, 1277: 7, 1278: 4, 1279: 4, 1280: 4, 1296: 4, 1300: 8, 1322: 6, 1323: 4, 1328: 4, 1345: 8, 1417: 8, 1512: 8, 1517: 8, 1601: 8, 1609: 8, 1613: 8, 1649: 8, 1792: 8, 1793: 8, 1798: 8, 1824: 8, 1825: 8, 1840: 8, 1842: 8, 1858: 8, 1860: 8, 1863: 8, 1872: 8, 1875: 8, 1882: 8, 1888: 8, 1889: 8, 1892: 8, 1906: 7, 1907: 7, 1912: 7, 1919: 7, 1920: 8, 1924: 8, 1930: 7, 1937: 8, 1953: 8, 1968: 8, 1969: 8, 1971: 8, 1975: 8, 1984: 8, 1988: 8, 2000: 8, 2001: 8, 2002: 8, 2016: 8, 2017: 8, 2018: 8, 2020: 8, 2021: 8, 2024: 8, 2026: 8
+  }],
 }
 
 FW_VERSIONS: dict[str, dict[tuple, list[bytes]]] = {
diff --git a/opendbc/car/gm/interface.py b/opendbc/car/gm/interface.py
index 3910ec64a1..25dc2c85de 100755
--- a/opendbc/car/gm/interface.py
+++ b/opendbc/car/gm/interface.py
@@ -7,7 +7,7 @@
 from opendbc.car.common.basedir import BASEDIR
 from opendbc.car.common.conversions import Conversions as CV
 from opendbc.car.gm.radar_interface import RADAR_HEADER_MSG
-from opendbc.car.gm.values import CAR, CarControllerParams, EV_CAR, CAMERA_ACC_CAR, CanBus
+from opendbc.car.gm.values import CAR, CarControllerParams, EV_CAR, CAMERA_ACC_CAR, SDGM_CAR, CanBus
 from opendbc.car.interfaces import CarInterfaceBase, TorqueFromLateralAccelCallbackType, FRICTION_THRESHOLD, LatControlInputs, NanoFFModel
 
 TransmissionType = structs.CarParams.TransmissionType
@@ -93,13 +93,13 @@ def _get_params(ret: structs.CarParams, candidate, fingerprint, car_fw, experime
 
     ret.longitudinalTuning.kiBP = [5., 35.]
 
-    if candidate in CAMERA_ACC_CAR:
-      ret.experimentalLongitudinalAvailable = True
+    if candidate in (CAMERA_ACC_CAR | SDGM_CAR):
+      ret.experimentalLongitudinalAvailable = candidate not in SDGM_CAR
       ret.networkLocation = NetworkLocation.fwdCamera
       ret.radarUnavailable = True  # no radar
       ret.pcmCruise = True
       ret.safetyConfigs[0].safetyParam |= Panda.FLAG_GM_HW_CAM
-      ret.minEnableSpeed = 5 * CV.KPH_TO_MS
+      ret.minEnableSpeed = -1 if candidate in SDGM_CAR else 5 * CV.KPH_TO_MS
       ret.minSteerSpeed = 10 * CV.KPH_TO_MS
 
       # Tuning for experimental long
@@ -191,4 +191,9 @@ def _get_params(ret: structs.CarParams, candidate, fingerprint, car_fw, experime
       ret.steerActuatorDelay = 0.2
       CarInterfaceBase.configure_torque_tune(candidate, ret.lateralTuning)
 
+    elif candidate == CAR.CADILLAC_XT4:
+      ret.steerActuatorDelay = 0.2
+      ret.minSteerSpeed = 30 * CV.MPH_TO_MS
+      CarInterfaceBase.configure_torque_tune(candidate, ret.lateralTuning)
+
     return ret
diff --git a/opendbc/car/gm/values.py b/opendbc/car/gm/values.py
index 1fbee8c256..bf16e61763 100644
--- a/opendbc/car/gm/values.py
+++ b/opendbc/car/gm/values.py
@@ -36,7 +36,7 @@ def __init__(self, CP):
     self.ZERO_GAS = 2048  # Coasting
     self.MAX_BRAKE = 400  # ~ -4.0 m/s^2 with regen
 
-    if CP.carFingerprint in CAMERA_ACC_CAR:
+    if CP.carFingerprint in (CAMERA_ACC_CAR | SDGM_CAR):
       self.MAX_GAS = 3400
       self.MAX_ACC_REGEN = 1514
       self.INACTIVE_REGEN = 1554
@@ -65,7 +65,10 @@ class GMCarDocs(CarDocs):
 
   def init_make(self, CP: CarParams):
     if CP.networkLocation == CarParams.NetworkLocation.fwdCamera:
-      self.car_parts = CarParts.common([CarHarness.gm])
+      if CP.carFingerprint in SDGM_CAR:
+        self.car_parts = CarParts.common([CarHarness.gmsdgm])
+      else:
+        self.car_parts = CarParts.common([CarHarness.gm])
     else:
       self.car_parts = CarParts.common([CarHarness.obd_ii])
 
@@ -86,6 +89,12 @@ def init(self):
     # ASCM is supported, but due to a janky install and hardware configuration, we are not showing in the car docs
     self.car_docs = []
 
+@dataclass
+class GMSDGMPlatformConfig(GMPlatformConfig):
+  def init(self):
+    # Don't show in docs until the harness is sold. See https://github.com/commaai/openpilot/issues/32471
+    self.car_docs = []
+
 
 class CAR(Platforms):
   HOLDEN_ASTRA = GMASCMPlatformConfig(
@@ -150,6 +159,10 @@ class CAR(Platforms):
     [GMCarDocs("Chevrolet Trailblazer 2021-22")],
     GMCarSpecs(mass=1345, wheelbase=2.64, steerRatio=16.8, centerToFrontRatio=0.4, tireStiffnessFactor=1.0),
   )
+  CADILLAC_XT4 = GMSDGMPlatformConfig(
+    [GMCarDocs("Cadillac XT4 2023", "Driver Assist Package")],
+    CarSpecs(mass=1660, wheelbase=2.78, steerRatio=14.4, centerToFrontRatio=0.4),
+  )
 
 
 class CruiseButtons:
@@ -229,6 +242,9 @@ class CanBus:
 # We're integrated at the camera with VOACC on these cars (instead of ASCM w/ OBD-II harness)
 CAMERA_ACC_CAR = {CAR.CHEVROLET_BOLT_EUV, CAR.CHEVROLET_SILVERADO, CAR.CHEVROLET_EQUINOX, CAR.CHEVROLET_TRAILBLAZER}
 
+# We're integrated at the Safety Data Gateway Module on these cars
+SDGM_CAR = {CAR.CADILLAC_XT4}
+
 STEER_THRESHOLD = 1.0
 
 DBC = CAR.create_dbc_map()
diff --git a/opendbc/car/tests/routes.py b/opendbc/car/tests/routes.py
index dac197642b..6695b4cbc2 100644
--- a/opendbc/car/tests/routes.py
+++ b/opendbc/car/tests/routes.py
@@ -70,6 +70,7 @@ class CarTestRoute(NamedTuple):
   CarTestRoute("555d4087cf86aa91|2022-12-02--12-15-07", GM.CHEVROLET_BOLT_EUV, segment=14),  # Bolt EV
   CarTestRoute("38aa7da107d5d252|2022-08-15--16-01-12", GM.CHEVROLET_SILVERADO),
   CarTestRoute("5085c761395d1fe6|2023-04-07--18-20-06", GM.CHEVROLET_TRAILBLAZER),
+  CarTestRoute("162796f1469f2f1b/00000005--6f334eda14", GM.CADILLAC_XT4),
 
   CarTestRoute("0e7a2ba168465df5|2020-10-18--14-14-22", HONDA.ACURA_RDX_3G),
   CarTestRoute("a74b011b32b51b56|2020-07-26--17-09-36", HONDA.HONDA_CIVIC),
diff --git a/opendbc/car/torque_data/override.toml b/opendbc/car/torque_data/override.toml
index a4fc2a479f..f4142ba1df 100644
--- a/opendbc/car/torque_data/override.toml
+++ b/opendbc/car/torque_data/override.toml
@@ -36,6 +36,7 @@ legend = ["LAT_ACCEL_FACTOR", "MAX_LAT_ACCEL_MEASURED", "FRICTION"]
 "SUBARU_OUTBACK" = [2.0, 1.5, 0.2]
 "CADILLAC_ESCALADE" = [1.899999976158142, 1.842270016670227, 0.1120000034570694]
 "CADILLAC_ESCALADE_ESV_2019" = [1.15, 1.3, 0.2]
+"CADILLAC_XT4" = [1.45, 1.6, 0.2]
 "CHEVROLET_BOLT_EUV" = [2.0, 2.0, 0.05]
 "CHEVROLET_SILVERADO" = [1.9, 1.9, 0.112]
 "CHEVROLET_TRAILBLAZER" = [1.33, 1.9, 0.16]