diff --git a/selfdrive/car/hyundai/tests/test_hyundai.py b/selfdrive/car/hyundai/tests/test_hyundai.py
index f0c6b05c00..5fa92624af 100755
--- a/selfdrive/car/hyundai/tests/test_hyundai.py
+++ b/selfdrive/car/hyundai/tests/test_hyundai.py
@@ -62,7 +62,7 @@ class TestHyundaiFingerprint(unittest.TestCase):
     # Asserts no ECUs known to be shared across platforms exist in the database.
     # Tucson having Santa Cruz camera and EPS for example
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         if car_model == CAR.SANTA_CRUZ_1ST_GEN:
           raise unittest.SkipTest("Skip checking Santa Cruz for its parts")
 
@@ -79,7 +79,7 @@ class TestHyundaiFingerprint(unittest.TestCase):
     """
     expected_fw_prefix = HYUNDAI_VERSION_REQUEST_LONG[1:]
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         for ecu, fws in ecus.items():
           # TODO: enable for Ecu.fwdRadar, Ecu.abs, Ecu.eps, Ecu.transmission
           if ecu[0] in (Ecu.fwdCamera,):
@@ -103,7 +103,7 @@ class TestHyundaiFingerprint(unittest.TestCase):
 
     # Asserts ECU keys essential for fuzzy fingerprinting are available on all platforms
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         for platform_code_ecu in PLATFORM_CODE_ECUS:
           if platform_code_ecu in (Ecu.fwdRadar, Ecu.eps) and car_model == CAR.HYUNDAI_GENESIS:
             continue
@@ -118,7 +118,7 @@ class TestHyundaiFingerprint(unittest.TestCase):
     # - expected parsing of ECU FW dates
 
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         for ecu, fws in ecus.items():
           if ecu[0] not in PLATFORM_CODE_ECUS:
             continue
diff --git a/selfdrive/car/tests/test_fw_fingerprint.py b/selfdrive/car/tests/test_fw_fingerprint.py
index 378b68e43e..6777aeb738 100755
--- a/selfdrive/car/tests/test_fw_fingerprint.py
+++ b/selfdrive/car/tests/test_fw_fingerprint.py
@@ -97,7 +97,7 @@ class TestFwFingerprint(unittest.TestCase):
 
   def test_fw_version_lists(self):
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         for ecu, ecu_fw in ecus.items():
           with self.subTest(ecu):
             duplicates = {fw for fw in ecu_fw if ecu_fw.count(fw) > 1}
@@ -119,13 +119,13 @@ class TestFwFingerprint(unittest.TestCase):
     for brand, config in FW_QUERY_CONFIGS.items():
       for car_model, ecus in VERSIONS[brand].items():
         bad_ecus = set(ecus).intersection(config.extra_ecus)
-        with self.subTest(car_model=car_model):
+        with self.subTest(car_model=car_model.value):
           self.assertFalse(len(bad_ecus), f'{car_model}: Fingerprints contain ECUs added for data collection: {bad_ecus}')
 
   def test_blacklisted_ecus(self):
     blacklisted_addrs = (0x7c4, 0x7d0)  # includes A/C ecu and an unknown ecu
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         CP = interfaces[car_model][0].get_non_essential_params(car_model)
         if CP.carName == 'subaru':
           for ecu in ecus.keys():
diff --git a/selfdrive/car/toyota/tests/test_toyota.py b/selfdrive/car/toyota/tests/test_toyota.py
index 5241a95a99..cdaef55269 100755
--- a/selfdrive/car/toyota/tests/test_toyota.py
+++ b/selfdrive/car/toyota/tests/test_toyota.py
@@ -26,7 +26,7 @@ class TestToyotaInterfaces(unittest.TestCase):
     # Asserts standard ECUs exist for each platform
     common_ecus = {Ecu.fwdRadar, Ecu.fwdCamera}
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         present_ecus = {ecu[0] for ecu in ecus}
         missing_ecus = common_ecus - present_ecus
         self.assertEqual(len(missing_ecus), 0)
@@ -55,7 +55,7 @@ class TestToyotaFingerprint(unittest.TestCase):
   def test_platform_code_ecus_available(self):
     # Asserts ECU keys essential for fuzzy fingerprinting are available on all platforms
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         for platform_code_ecu in PLATFORM_CODE_ECUS:
           if platform_code_ecu == Ecu.eps and car_model in (CAR.PRIUS_V, CAR.LEXUS_CTH,):
             continue
@@ -70,7 +70,7 @@ class TestToyotaFingerprint(unittest.TestCase):
     # - expected parsing of ECU sub-versions
 
     for car_model, ecus in FW_VERSIONS.items():
-      with self.subTest(car_model=car_model):
+      with self.subTest(car_model=car_model.value):
         for ecu, fws in ecus.items():
           if ecu[0] not in PLATFORM_CODE_ECUS:
             continue