| U1000 | Class 2 Communication Malfunction |
| U1001-U1254 | Loss of XXX Communications |
| U1002 | Loss of serial communications for class 2 devices |
| U1003 | Loss of serial communications for class 2 devices |
| U1004 | Loss of serial communications for class 2 devices |
| U1005 | Loss of serial communications for class 2 devices |
| U1006 | Loss of serial communications for class 2 devices |
| U1007 | Loss of serial communications for class 2 devices |
| U1008 | Loss of serial communications for class 2 devices |
| U1009 | Loss of serial communications for class 2 devices |
| U1010 | Loss of serial communications for class 2 devices |
| U1011 | Loss of serial communications for class 2 devices |
| U1012 | Loss of serial communications for class 2 devices |
| U1013 | Loss of serial communications for class 2 devices |
| U1014 | Loss of serial communications for class 2 devices |
| U1015 | Loss of serial communications for class 2 devices |
| U1016 | Loss of Class 2 Communication with VCM |
| U1016 | Loss of Communications with PCM |
| U1017 | Loss of serial communications for class 2 devices |
| U1018 | Loss of serial communications for class 2 devices |
| U1019 | Loss of serial communications for class 2 devices |
| U1020 | Loss of serial communications for class 2 devices |
| U1021 | Loss of serial communications for class 2 devices |
| U1022 | Loss of serial communications for class 2 devices |
| U1023 | Loss of serial communications for class 2 devices |
| U1024 | Loss of serial communications for class 2 devices |
| U1025 | Loss of serial communications for class 2 devices |
| U1026 | Loss of ATC Class 2 Communication |
| U1027 | Loss of serial communications for class 2 devices |
| U1028 | Loss of serial communications for class 2 devices |
| U1029 | Loss of serial communications for class 2 devices |
| U1030 | Loss of serial communications for class 2 devices |
| U1031 | Loss of serial communications for class 2 devices |
| U1032 | Loss of serial communications for class 2 devices |
| U1033 | Loss of serial communications for class 2 devices |
| U1034 | Loss of serial communications for class 2 devices |
| U1035 | Loss of serial communications for class 2 devices |
| U1036 | Loss of serial communications for class 2 devices |
| U1037 | Loss of serial communications for class 2 devices |
| U1038 | Loss of Serial Communications for Class 2 Devices |
| U1039 | Loss of Serial Communications for Class 2 Devices |
| U1040 | Loss of Class 2 Communications with ABS |
| U1041 | Loss of EBCM Communication |
| U1042 | Lost Communications with Brake/Traction Control System |
| U1043 | Loss of Serial Communications for Class 2 Devices |
| U1044 | Loss of Serial Communications for Class 2 Devices |
| U1045 | Loss of Serial Communications for Class 2 Devices |
| U1046 | Loss of Serial Communications for Class 2 Devices |
| U1047 | Loss of Serial Communications for Class 2 Devices |
| U1048 | Loss of Serial Communications for Class 2 Devices |
| U1049 | Loss of Serial Communications for Class 2 Devices |
| U1050 | Loss of Serial Communications for Class 2 Devices |
| U1051 | Loss of Serial Communications for Class 2 Devices |
| U1052 | Loss of Serial Communications for Class 2 Devices |
| U1053 | Loss of Serial Communications for Class 2 Devices |
| U1054 | Loss of Serial Communications for Class 2 Devices |
| U1055 | Loss of Serial Communications for Class 2 Devices |
| U1056 | Loss of Communications with RSS |
| U1057 | Loss of Serial Communications for Class 2 Devices |
| U1058 | Loss of Serial Communications for Class 2 Devices |
| U1059 | Loss of Serial Communications for Class 2 Devices |
| U1060 | Loss of Serial Communications for Class 2 Devices |
| U1161 | Loss of PDM Serial Data |
| U1062 | Loss of Serial Communications for Class 2 Devices |
| U1163 | Loss of RRDM Serial Data |
| U1064 | Loss of Communications with DIM |
| U1065 | Loss of Communications with IPM |
| U1066 | Loss of Communications with RIM |
| U1067 | Loss of Serial Communications for Class 2 Devices |
| U1068 | Loss of Serial Communications for Class 2 Devices |
| U1069 | Loss of Serial Communications for Class 2 Devices |
| U1170 | Loss of Driver Door Sw Asm Serial Data |
| U1071 | Loss of Serial Communications for Class 2 Devices |
| U1072 | Loss of Serial Communications for Class 2 Devices |
| U1073 | Loss of Serial Communications for Class 2 Devices |
| U1074 | Loss of Serial Communications for Class 2 Devices |
| U1075 | Loss of Serial Communications for Class 2 Devices |
| U1076 | Loss of Serial Communications for Class 2 Devices |
| U1077 | Loss of Serial Communications for Class 2 Devices |
| U1078 | Loss of Serial Communications for Class 2 Devices |
| U1079 | Loss of Serial Communications for Class 2 Devices |
| U1080 | Loss of Serial Communications for Class 2 Devices |
| U1081 | Loss of Serial Communications for Class 2 Devices |
| U1082 | Loss of Serial Communications for Class 2 Devices |
| U1083 | Loss of Serial Communications for Class 2 Devices |
| U1084 | Loss of Serial Communications for Class 2 Devices |
| U1085 | Loss of Serial Communications for Class 2 Devices |
| U1086 | Loss of Serial Communications for Class 2 Devices |
| U1087 | Loss of Serial Communications for Class 2 Devices |
| U1088 | Loss of Communications with SDM |
| U1089 | Loss of Serial Communications for Class 2 Devices |
| U1090 | Loss of Serial Communications for Class 2 Devices |
| U1091 | Loss of Serial Communications for Class 2 Devices |
| U1092 | Loss of Serial Communications for Class 2 Devices |
| U1093 | Loss of Serial Communications for Class 2 Devices |
| U1094 | Loss of Serial Communications for Class 2 Devices |
| U1095 | Loss of Serial Communications for Class 2 Devices |
| U1096 | Loss of Communications with IPC |
| U1097 | Loss of Serial Communications for Class 2 Devices |
| U1098 | Loss of Serial Communications for Class 2 Devices |
| U1099 | Loss of Serial Communications for Class 2 Devices |
| U1100 | Loss of Serial Communications for Class 2 Devices |
| U1101 | Loss of Serial Communications for Class 2 Devices |
| U1102 | Loss of Serial Communications for Class 2 Devices |
| U1103 | Loss of Serial Communications for Class 2 Devices |
| U1104 | Loss of Serial Communications for Class 2 Devices |
| U1105 | Loss of Serial Communications for Class 2 Devices |
| U1106 | Loss of Serial Communications for Class 2 Devices |
| U1107 | Loss of Serial Communications for Class 2 Devices |
| U1108 | Loss of Serial Communications for Class 2 Devices |
| U1109 | Loss of Serial Communications for Class 2 Devices |
| U1110 | Loss of Serial Communications for Class 2 Devices |
| U1111 | Loss of Serial Communications for Class 2 Devices |
| U1112 | Loss of Serial Communications for Class 2 Devices |
| U1113 | Loss of Serial Communications for Class 2 Devices |
| U1114 | Loss of Serial Communications for Class 2 Devices |
| U1115 | Loss of Serial Communications for Class 2 Devices |
| U1116 | Loss of Serial Communications for Class 2 Devices |
| U1117 | Loss of Serial Communications for Class 2 Devices |
| U1118 | Loss of Serial Communications for Class 2 Devices |
| U1119 | Loss of Serial Communications for Class 2 Devices |
| U1120 | Loss of Serial Communications for Class 2 Devices |
| U1121 | Loss of Serial Communications for Class 2 Devices |
| U1122 | Loss of Serial Communications for Class 2 Devices |
| U1123 | Loss of serial communications for class 2 devices |
| U1124 | Loss of serial communications for class 2 devices |
| U1125 | Loss of serial communications for class 2 devices |
| U1126 | Loss of serial communications for class 2 devices |
| U1127 | Loss of serial communications for class 2 devices |
| U1128 | Loss of Communications with IRC |
| U1129 | Loss of Communications with AMP |
| U1130 | Loss of serial communications for class 2 devices |
| U1131 | Loss of serial communications for class 2 devices |
| U1132 | Loss of serial communications for class 2 devices |
| U1133 | Loss of serial communications for class 2 devices |
| U1134 | Loss of serial communications for class 2 devices |
| U1135 | Loss of serial communications for class 2 devices |
| U1136 | Loss of serial communications for class 2 devices |
| U1137 | Loss of serial communications for class 2 devices |
| U1138 | Loss of serial communications for class 2 devices |
| U1139 | Loss of serial communications for class 2 devices |
| U1140 | Loss of serial communications for class 2 devices |
| U1141 | Loss of serial communications for class 2 devices |
| U1142 | Loss of serial communications for class 2 devices |
| U1143 | Loss of serial communications for class 2 devices |
| U1144 | Loss of Communications with PHN |
| U1145 | Loss Of NAV Communications |
| U1146 | Loss Of Onstar Communiction |
| U1147 | Loss of serial communications for class 2 devices |
| U1148 | Loss of serial communications for class 2 devices |
| U1149 | Loss of serial communications for class 2 devices |
| U1150 | Loss of serial communications for class 2 devices |
| U1151 | Loss of serial communications for class 2 devices |
| U1152 | Loss Of ACM Serial Data Communication |
| U1152 | Loss of Data HCM |
| U1153 | Loss of Communications with CCP |
| U1154 | Loss of serial communications for class 2 devices |
| U1155 | Loss of serial communications for class 2 devices |
| U1156 | Loss of serial communications for class 2 devices |
| U1157 | Loss of serial communications for class 2 |
| U1158 | Loss of serial communications for class 2 devices |
| U1159 | Loss of serial communications for class 2 devices |
| U1160 | Loss of Communications with DDM |
| U1161 | Loss of PASS Door Module SBI |
| U1162 | Loss of Rear Driver Door Module SBI |
| U1163 | Loss of Rear PASS Door Module SBI |
| U1164 | Loss Of DIM Serial Data Communication |
| U1165 | Loss of serial communications for class 2 devices |
| U1166 | Loss of Communications with SCM |
| U1167 | Loss of serial communications for class 2 devices |
| U1168 | Loss Of TTM Communications |
| U1169 | Loss of Communications with MMM |
| U1170 | Loss of Driver Door Switch SBI |
| U1171 | Loss of serial communications for class 2 devices |
| U1172 | Loss of serial communications for class 2 devices |
| U1173 | Loss of serial communications for class 2 devices |
| U1174 | Loss of serial communications for class 2 devices |
| U1175 | Loss of serial communications for class 2 devices |
| U1176 | Loss Of RFA Communications |
| U1177 | Loss of serial communications for class 2 devices |
| U1178 | Loss of serial communications for class 2 devices |
| U1179 | Loss of serial communications for class 2 devices |
| U1180 | Loss of serial communications for class 2 devices |
| U1181 | Loss of serial communications for class 2 devices |
| U1182 | Loss of serial communications for class 2 devices |
| U1183 | Loss of serial communications for class 2 devices |
| U1184 | Loss of serial communications for class 2 devices |
| U1185 | Loss of serial communications for class 2 devices |
| U1186 | Loss of serial communications for class 2 devices |
| U1187 | Loss of serial communications for class 2 devices |
| U1188 | Loss of serial communications for class 2 devices |
| U1189 | Loss of serial communications for class 2 devices |
| U1190 | Loss of serial communications for class 2 devices |
| U1191 | Loss of serial communications for class 2 devices |
| U1192 | Loss of VTD Class 2 Serial Data Com |
| U1193 | Loss of VIM Class 2 Communication |
| U1194 | Loss of serial communications for class 2 devices |
| U1195 | Loss of serial communications for class 2 devices |
| U1196 | Loss of serial communications for class 2 devices |
| U1197 | Loss of serial communications for class 2 devices |
| U1198 | Loss of serial communications for class 2 devices |
| U1199 | Loss of serial communications for class 2 devices |
| U1200 | Loss of serial communications for class 2 devices |
| U1201 | Loss of serial communications for class 2 devices |
| U1202 | Loss of serial communications for class 2 devices |
| U1203 | Loss of serial communications for class 2 devices |
| U1204 | Loss of serial communications for class 2 devices |
| U1205 | Loss of serial communications for class 2 devices |
| U1206 | Loss of serial communications for class 2 devices |
| U1207 | Loss of serial communications for class 2 devices |
| U1208 | Loss of serial communications for class 2 devices |
| U1209 | Loss of serial communications for class 2 devices |
| U1210 | Loss of serial communications for class 2 devices |
| U1215 | Loss of serial communications for class 2 devices |
| U1220 | Loss of serial communications for class 2 devices |
| U1225 | Loss of serial communications for class 2 devices |
| U1230 | Loss of serial communications for class 2 devices |
| U1235 | Loss of serial communications for class 2 devices |
| U1240 | Loss of serial communications for class 2 devices |
| U1245 | Loss of serial communications for class 2 devices |
| U1250 | Loss of serial communications for class 2 devices |
| U1251 | Loss of serial communications for class 2 devices |
| U1252 | Loss of serial communications for class 2 devices |
| U1253 | Loss of serial communications for class 2 devices |
| U1254 | Loss of serial communications for class 2 devices |
| U1255 | Class 2 Communication Malfunction |
| U1255 | Serial Data Line Malfunction |
| U1300 | Class 2 Short to Ground |
| U1301 | Class 2 Short to Battery |
| U1304 | Loss Of UART Communications |
| U1305 | Class 2 Data Link Low or High |
| U1500 | Inter-Device Dedicated Bus Malfunction |
| U2000 | Invalid BFC Transmitted SPI Data |
| U2001 | Invalid IPC Transmitted SPI Data |
| U2002 | SPI Data-In Low |
| U2003 | SPI Data-In High |
| U2004 | SPI Data-Out Low |
| U2005 | SPI Data-Out High |
| U2006 | SPI Clock-Out Low |
| U2007 | SPI Clock-Out High |
| U2050 | SIR PPS/CPS Communications Link malfunction |
| U2100 | CAN Bus OFF |
| U2100 | CAN-BUS Communication Malfunction |
| U2102 | More Controllers on Bus than Programmed |
| U2103 | Fewer Controllers On Bus Than Programmed |
| U2104 | CAN Bus Reset Counter Overrun |
| U2105 | CAN Bus Error ECM |
| U2105 | Lost Comm with Engine Control System |
| U2106 | Lost Comm with Trans Control System |
| U2107 | Lost Communications with Body Control System |
| U2108 | CAN Bus Error ABS |
| U2108 | Lost Comm with ABS Control System |
| U2150 | Navigation ECU Gateway Communication Error |
| U2151 | Navigation ECU Communication Malfunction |
| U2153 | VICS ECU Communication Error |
