Control Module U Code List
This list includes all Data Communications related U-code DTCs in alphanumeric order with descriptors for all modules. Not all DTCs listed will be applicable to all vehicles.
| DTC | DTC Descriptor |
|---|---|
| U0001 00 | High Speed CAN Bus Malfunction |
| U0002 00 | High Speed CAN Bus |
| U0020 00 | Low Speed CAN Bus |
| U0073 00 | Control Module Communication Bus A Off |
| U0073 71 | ECU HS Bus Off |
| U0073 72 | ECU LS Bus Off |
| U0074 00 | Control Module Communication Bus B Off |
| U0075 00 | Control Module Communication Bus "C" Off |
| U0100 00 | Lost Communication with Engine/Powertrain Control Module (ECM/PCM) |
| U0100 75 | Lost Communication with Engine/Powertrain Control Module (ECM) |
| U0100 7F | Lost Communication with Engine/Powertrain Control Module (ECM) |
| U0101 00 | Lost Communication with Transmission Control Module (TCM) |
| U0101 75 | Lost Communication with Transmission Control Module (TCM) |
| U0102 00 | Lost Communication with Transfer Case Control Module |
| U0104 00 | Lost Communication with Cruise Control Module |
| U0104 7F | Lost Communication with Cruise Control Module |
| U0106 00 | Lost Communication with Glow Plug Control Module |
| U0109 00 | Lost Communication with Fuel Pump Control Module |
| U010F 00 | Lost Communication with Air Conditioning Control Module |
| U0111 00 | Lost Communication with Battery Energy Control Module |
| U0117 00 | Lost Communication Electrical PTO Control Module |
| U0121 00 | Lost Communication with Electronic Brake Control Control Module (EBCM) |
| U0122 00 | Lost Communication with Vehicle Stability Control Module |
| U0123 00 | Lost Communication with Yaw Rate Sensor Module |
| U0128 00 | Lost Communication with Park Brake Control Module |
| U0129 00 | Lost Communication with Brake System Control Module |
| U0131 00 | Lost Communication with Power Steering Control Module |
| U0132 00 | Lost Communication with Ride Level Control Module |
| U0134 00 | Lost Communication with Power Steering Control Module - Rear |
| U0136 00 | Lost Communication with Differential Control Module - Rear |
| U0137 00 | Lost Communication with Trailer Brake Control Module |
| U0140 00 | Lost Communication with Body Control Module |
| U0141 00 | Lost Communication with Body Control Module A |
| U0144 00 | Lost Communication with Body Control Module "D" |
| U0146 00 | Lost Communication with Gateway A |
| U0151 00 | Lost Communication with Inflatable Restraint Sensing and Diagnostic Module (SDM) |
| U0151 71 | Lost Communication with Inflatable Restraint Sensing and Diagnostic Module (SDM) Invalid Serial Data Received |
| U0151 7F | Lost Communication with Restraints Control Inflatable Restraint Sensing and Diagnostic Module (SDM) Erratic |
| U0155 00 | Lost Communication with Instrument Panel Cluster (IPC) Control Module |
| U0156 00 | Lost Communication with Information Center A (DIC) |
| U0158 00 | Lost Communication with Head Up Display |
| U0159 00 | Lost Communication with Park Assist Module (RPA) |
| U0160 00 | Lost Communication with Audible Alert Control Module |
| U0164 00 | Lost Communication with HVAC Control Module |
| U0165 00 | Loss of Communication with HVAC Control Module - Rear |
| U0168 00 | Lost Communication with Vehicle Security Control Module |
| U0170 00 | Lost Communication with Restraints System Sensor A (PPS) |
| U0172 00 | Lost Communication with Rollover Sensor |
| U0173 00 | Lost Communication with "Restraints System Sensor D" |
| U0181 00 | Lost Communication with Headlamp Leveling Control Module |
| U0184 00 | Lost Communication with Radio |
| U0186 00 | Lost Communication with Audio Amplifier |
| U0191 00 | Lost Communication with Television |
| U0194 00 | Lost Communication with Digital Radio Receiver (DRR) |
| U0196 00 | Lost Communication with Rear Audio Control Module |
| U0198 00 | Lost Communication with Telematic Control Module |
| U0199 00 | Lost Communication with Door Control Module A (DDM) |
| U0200 00 | Lost Communication with Door Control Module B (PDM) |
| U0208 00 | Lost Communication with Seat Control Module A (DSM/MSM) |
| U0209 00 | Lost Communication with Seat Control Module B (HVSM) |
| U0210 00 | Lost Communication with Seat Control Module C (RHSM) |
| U0214 00 | Lost Communication with Remote Function Actuation |
| U0230 00 | Lost Communication with Rear Gate Module |
| U0232 00 | Lost Communication with Side Object Detection (SOD) Module - Left |
| U0233 00 | Lost Communication with Side Object Detection (SOD) Module - Right |
| U0236 00 | Lost Communication with Column Locking Module (CLM) |
| U023A 00 | Lost Communication with Vehicle Direction Camera Control Module (Lane Departure Warning) |
| U0241 00 | Lost Communication with Headlamp Control Module A |
| U0249 00 | Loss of Communication with Entertainment Control Module - Rear B |
| U0255 00 | Loss of Communication with Front Display Interface Module |
| U0256 00 | Loss of Communication with Front Controls Interface Module |
| U0257 00 | Loss of Communication with Front Controls/Display Interface Module |
| U0293 00 | Lost Communication with with HP2 Powertrain Control Module |
| U180F | Control Module Communication Bus B Off |
| U1000 | Class 2 Data Link Malfunction |
| U1016 | Lost Communication with ECM / PCM |
| U1017 | Lost Communication with Engine Control System |
| U1024 | Lost Communication with Transmission Control Module |
| U1026 | Lost Communication with Transfer Case Control Module |
| U1040 | Lost Communication with Electronic Brake Control Module |
| U1064 | Lost Communication with Body Control Module / Dash Integration Module |
| U1088 | Lost Communication with Inflatable Restraint Sensing and Diagnostic Module |
| U1096 | Lost Communication with Instrument Panel Cluster |
| U1098 | Lost Communication with Secondary Information Center |
| U1099 | Lost Communication with Head Up Display |
| U1100 | Lost Communication with "Driver Information and Displays Control System" |
| U1128 | Lost Communication with Radio |
| U1129 | Lost Communication with Amplifier |
| U1133 | Lost Communication with Mini Disc Changer |
| U1137 | Lost Communication with Satellite Digital Audio Reception System (DRR) |
| U1153 | Lost Communication with Climate Control Panel |
| U1164 | Lost Communication with Driver Door Switch |
| U1165 | Lost Communication with Passenger Door Switch |
| U1176 | Lost Communication with Remote Function Actuation |
| U1177 | Lost Communication with Folding Top Controller |
| U1193 | Lost Communication with Remote Control Door Lock Receiver |
| U1255 | Loss of Class 2 Communication |
| U1300 | Class 2 Data Link Low |
| U1301 | Class 2 Data Link high |
| U1305 | Class 2 Data Link high or Low |
| U1500 01 | Inter-Device Dedicated Bus 1 Short to Battery |
| U1500 02 | Inter-Device Dedicated Bus 1 Short to Ground |
| U1511 00 | Inter-device Dedicated Bus Lost Communication with Device 1 |
| U1512 00 | Inter-device Dedicated Bus Lost Communication with Device 2 |
| U1513 00 | LIN Bus 1 Lost Communication with Device 3 |
| U1650 00 | Chassis System Dedicated Bus Controller |
| U1651 00 | Chassis System Dedicated Bus Sensor |
| U180F 00 | Control Module Communication Bus B Off |
| U1802 00 | Lost Communication with Fuel Pump Control Module |
| U1812 00 | Battery Energy Control Module Bus B High Speed Communication Enable Circuit Low |
| U1813 00 | Battery Energy Control Module Bus B High Speed Communication Enable Circuit High |
| U1814 00 | Powertrain High Speed Communication Enable Circuit |
| U1815 00 | Lost Communication with Drive Motor Control Module A on Bus B |
| U1816 00 | Lost Communication with Drive Motor Control Module B on Bus B |
| U1817 00 | Lost Communication with Hybrid Powertrain Control Module on Bus B |
| U1818 00 | Lost Communication with ECM/PCM A on Bus B |
| U1820 00 | Lost Communication with Brake System Control Module on Bus B |
| U1821 00 | Lost Communication with DC to DC Converter Control Module A on Bus B |
| U1822 00 | Lost Communications with Active Front Steering (AFS) Control Module on Bus B |
| U1823 00 | Lost Communications with Antilock Brake System (ABS) Control Module on Bus B |
| U1824 00 | Lost Communications with Ride Level Control Module |
| U1825 00 | Lost Communications with SCM (CAN) |
| U1826 71 | Lost Communication with Multi-Axis Acceleration Sensor Module on Bus "B" Invalid Serial Data Received |
| U1826 72 | Lost Communication with Multi-Axis Acceleration Sensor Module on Bus "B" Alive Counter Incorrect/Not Updated |
| U1826 7F | Lost Communication with Multi-Axis Acceleration Sensor Module on Bus "B" Erratic |
| U1827 71 | Lost Communication with Steering Angle Sensor Module on Bus "B" Invalid Serial Data |
| U1827 72 | Lost Communication with Steering Angle Sensor Module on Bus "B" Alive Counter Incorrect/Not Updated |
| U1827 74 | Lost Communication with Steering Angle Sensor Module on Bus "B" Value of Signal Protection Calculation Incorrect |
| U1827 7F | Lost Communication with Steering Angle Sensor Module on Bus "B" Erratic |
| U182A 00 | Lost Communication with Battery Energy Control Module on Bus B |
| U1842 00 | Electronic Brake Control Module Lost Communication with Engine Control Module on Bus B |
| U1843 00 | Electronic Brake Control Module Lost Communication with Hybrid Engine Control Module on Bus B |
| U1862 00 | Battery Energy Control Module Lost Communication with Communications Gateway Module |
| U1863 00 | Starter/Generator Control Module Lost Communication with Body Control Module |
| U1865 00 | Fuel Operated Heater Lost Communication with Engine Control Module |
| U1866 00 | Battery Energy Control Module Lost Communication with Body Control Module |
| U186A 00 | Lost Communication with Transfer Case Control Module |
| U186B 00 | Lost Communication with TCM |
| U1875 00 | Drive Motor A Control Module Lost Communication with Battery Energy Control Module |
| U1876 00 | Drive Motor A Control Module Lost Communication with Engine Control Module (ECM)/Powertrain Control Module (PCM) |
| U1878 00 | Drive Motor B Control Module Lost Communication with Battery Energy Control Module |
| U1879 00 | Drive Motor B Control Module Lost Communication with Engine Control Module (ECM)/Powertrain Control Module (PCM) |
| U1885 00 | Battery Energy Control Module Lost Communication with with HP2 Powertrain Control Module |
| U1886 00 | Battery Energy Control Module Lost Communication with Engine Control Module (ECM) |
| U1888 00 | Lost Communication with Battery Pack |
| U1897 00 | Starter/Generator Control Module Lost Communication with Battery Energy Control Module |
| U1899 00 | Starter/Generator Control Module Lost Communication with Engine Control Module/Powertrain Control Module |
| U189A 00 | DC to DC Converter Control Module A Lost Communication with with HP2 Powertrain Control Module |
| U2099 00 | High Speed Communication Enable Circuit |
| U209A 00 | High Speed Communication Enable Circuit Low |
| U209D 00 | Battery Energy Control Module High Speed Communication Enable Circuit High |
| U2100 00 | Controller Area Network (CAN) Bus Communication |
| U2100 47 | Controller Area Network (CAN) Bus Communication |
| U2102 00 | Fewer Controllers On Bus Than Programmed |
| U2103 00 | Fewer Controllers On Bus Than Programmed |
| U2105 00 | Lost Communication with Engine Control Module |
| U2106 00 | Lost Communication with Transmission Control Module |
| U2107 00 | Lost Communication with Body Control Module |
| U2108 00 | Lost Communication with ABS/TCS Control System |
| U2109 00 | Lost Communication with Powertrain Control Module |
| U2110 00 | Lost Communication with Chassis Multiple Control System |
| U2111 00 | Lost Communication with Steering Control Module |
| U2112 00 | Lost Communication with Electronic Suspension Control (ESC) |
| U2113 00 | Lost Communication with Sensing and Diagnostic Module (SDM) |
| U2114 00 | Lost Communication with PPS or CPS |
| U2115 00 | Lost Communication with (Restraints Control System) |
| U2116 00 | Lost Communication with Instrument Cluster |
| U2117 00 | Lost Communication with Info Display |
| U2118 00 | Lost Communication with Head Up Display (HUD) |
| U2119 00 | Lost Communication with Daytime Running Lamps Control Module |
| U2120 00 | Lost Communication with Automatic Headlamp Leveling Control Module |
| U2121 00 | Lost Communication with Radio Display |
| U2122 00 | Lost Communication with Radio |
| U2123 00 | Lost Communication with Compact Disc Changer (CDX) |
| U2124 00 | Lost Communication with Audio Amplifier |
| U2125 00 | Lost Communication with Telematic Unit |
| U2126 00 | Lost Communication with Mobile Communications Control System |
| U2127 00 | Lost Communication with Front HVAC Control Module |
| U2128 00 | Lost Communication with Rear HVAC Control Module |
| U2129 00 | Lost Communication with Remote Function Actuator (RFA) |
| U2130 00 | Lost Communication with Driver Door Module (DDM) |
| U2131 00 | Lost Communication with Driver Seat Module (DSM) |
| U2132 00 | Lost Communication with Passenger Door Module (PDM) |
| U2133 00 | Lost Communication with Passenger Seat Module (PSM) |
| U2134 00 | Lost Communication with Rear Door Module (RDM) |
| U2135 00 | Lost Communication with Rear Integration Module (RIM) |
| U2136 00 | Lost Communication with Memory Mirror Module (MMM) |
| U2137 00 | Lost Communication with Vehicle Theft Deterrent (VTD) |
| U2138 00 | Lost Communication with Column Locking Module (CLM) |
| U2139 00 | Lost Communication with Column Integration Module (CIM) |
| U2140 00 | Lost Communication with Underhood Electrical Center (UEC) |
| U2141 00 | Lost Communication with Rear Electrical Center |
| U2142 00 | Lost Communication with Yaw Rate Sensor (YRS) |
| U2143 00 | Lost Communication with Steering Angle Sensor (SAS) |
| U2144 00 | Lost Communication with Distance Sensing Cruise Control Module |
| U2145 00 | Lost Communication with Parking Assistance System (PAS) |
| U2146 00 | Lost Communication with Shift Lever Module (SLM) |
| U2147 00 | Lost Communication with Auxiliary Heater System (AHS) |
| U2148 00 | Lost Communication with Sun Roof Module (SRM) |
| U2149 00 | Lost Communication with Tire Pressure Monitor (TPM) System |
| U2150 00 | Navigation Electronic Control Unit (ECU) Gateway Communications |
| U2151 00 | Navigation Electronic Control Unit (ECU) Communications |
| U2152 00 | Navigation Bus Request Line Circuit Low |
| U2153 00 | Navigation Electronic Control Unit (ECU) - VICS Communication Circuit |
| U2160 00 | Lost Communication with Steering Control System Sensor |
| U2161 00 | Lost Communication with Dash Integration Module (DIM) |
| U2162 00 | Lost Communication with Instrument Panel integration Module (IPM) |
| U2163 00 | Lost Communication with Left Rear Door Module (LRDM) |
| U2164 00 | Lost Communication with Right Rear Door Module (RRDM) |
| U2165 00 | Lost Communication with Driver Door Switch (DDS) |
| U2166 00 | Lost Communication with Driver Position Module (DPM) |
| U2167 00 | Lost Communication with Remote Control Door Lock Receiver (RCDLR) |
| U2168 00 | Lost Communication with Side Object Detection (SOD) Module - Left |
| U2169 00 | Lost Communication with Side Object Detection (SOD) Module - Right |
| U2170 00 | Lost Communication with Four Wheel Drive (4WD) Clutch |
| U2171 00 | Lost Communication with Rear Seat Entertainment (RSE) |
| U2172 00 | Lost Communication with Digital Radio Receiver (DRR) |
| U2173 00 | Lost Communication with Passive Entry and Passive Start System |
| U2174 00 | Lost Communication with Parking Heater System |
| U2175 00 | Lost Communication with Special Vehicle Module |
| U2176 00 | Lost Communication with Power Take Off (PTO) Control Module |
| U2177 00 | Lost Communication with Cruise Control Module |
| U2178 00 | Lost Communication with Trailer Interface Module |
| U2179 00 | Lost Communication with Television Module |
| U2180 00 | Lost Communication with Folding Top Control Module |
| U2181 00 | Lost Communication with Moveable Roof Module |
Circuit/System Verification
If this DTC is retrieved as a current DTC, replace the module that set the DTC.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for module replacement, setup, and programming
Reference Information
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool References
Control Module References for Scan Tool Information
Verify that DTC B1004 is not set.
- If the DTC is set, perform the setup procedure on the applicable control module, if the DTC resets replace the module.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for control module replacement, setup, and programming
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool References
Control Module References for scan tool information
Verify that DTC B1009 is not set.
- If the DTC is set, perform the Restrain ID relearn on the control module. If the DTC resets, replace the applicable control module.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for control module replacement, setup, and programming
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information.
With a scan tool, attempt to communicate with all modules.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool References
Control Module References for scan tool information
Schematic Reference
- «Data Communication Schematics»(ref-338128-S15254521082009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000)
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information
Verify that following BCM DTCs are not present
- U1814
- U2099
- B1428
- B1370
- B1380
- B1440
- B1441 If any listed DTC is present, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-338149-S32129793932009081700000) to diagnose that DTC prior to this diagnostic.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming
Schematic Reference
- «Data Communication Schematics»(ref-338128-S15254521082009081700000)
- «Antilock Brake System Schematics (JL7)»(ref-338158-S14943398672009081700000) or «Antilock Brake System Schematics (Except JL7)»(ref-338158-S13885188012009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000)
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information
With scan tool installed, clear the DTCs then drive the vehicle in a straight line at a speed greater than 20 km/h (13 mph). If the DTC did not set as a current DTC see Diagnostic Aids.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement»(ref-338158-S11616275812009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming
Schematic Reference
- «Data Communication Schematics»(ref-338128-S15254521082009081700000)
- «Antilock Brake System Schematics (JL7)»(ref-338158-S14943398672009081700000) or «Antilock Brake System Schematics (Except JL7)»(ref-338158-S13885188012009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000)
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information
With the scan tool perform the Steering Angle Sensor Centering, refer to Steering Angle Sensor Centering .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement»(ref-338158-S11616275812009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
Action Taken When the DTCs Sets
The module uses default values for the missing IPM data.
Diagnosis of this DTC is accomplished via the symptom, DTC U0100-U0299 .
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information.
With a scan tool, attempt to communicate with all modules.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information.
With a scan tool, attempt to communicate with all modules.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information.
With a scan tool, attempt to communicate with all modules.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information.
With a scan tool, attempt to communicate with all modules.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information.
With a scan tool, attempt to communicate with all modules.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
Schematic Reference
- «Data Communication Schematics»(ref-338128-S15254521082009081700000)
- «Antilock Brake System Schematics (JL7)»(ref-338158-S14943398672009081700000) or «Antilock Brake System Schematics (Except JL7)»(ref-338158-S13885188012009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000)
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement»(ref-338158-S11616275812009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming
Schematic Reference
Control Module References
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool References
Data Link Communications Description and Operation for Scan Tool information.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Data Communication Schematics»(ref-338128-S15254521082009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000)
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool References
Control Module References for scan tool information
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming
Symptoms - Data Communications
| IMPORTANT | The following steps must be completed before using the symptom tables. |
- Perform the «Diagnostic System Check - Vehicle»(ref-338149-S41903538652009081700000) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data links.
- Review the system operation in order to familiarize yourself with the system functions. Refer to: «Data Link Communications Description and Operation»(ref-338128-S34383779532009081700000) «Body Control System Description and Operation»(ref-338128-S39025277562009081700000)
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool References
Control Module References for scan tool information
- Ignition OFF, test for less than 5 ohm between terminal 4 at the data link connector (DLC) and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
- Ignition OFF, test for less than 5 ohm between the DLC terminal 5 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
- Ignition ON, test for B+ between the DLC terminals 16 and ground. If not the specified value, test the B+ circuit for a short to ground or an open/high resistance.
- If all circuits test normal, refer to the scan tool user guide.
Schematic Reference
- «Data Communication Schematics»(ref-338128-S15254521082009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000)
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Scan Tool Reference
Control Module References for scan tool information
Perform the Diagnostic Repair Verification after completing the repair.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for control module replacement, setup, and programming
Schematic Reference
Data Communication Schematics
Connector End View Reference
- «Component Connector End Views»(ref-338150-S01247117932009081700000)
- «Splice Pack Connector End Views»(ref-338150-S11722560152009081700000)
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
- «Circuit Testing»(ref-338151-S30248766082009081700000)
- «Connector Repairs»(ref-338151-S41110648952009081700000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-338151-S41477264612009081700000)
- «Wiring Repairs»(ref-338151-S09708660722009081700000)
Perform the Diagnostic Repair Verification after completing the repair.
- «GMLAN Wiring Repairs»(ref-338151-S16436757852009081700000)
- «Control Module References»(ref-338152-S12253781062009081700000) for module replacement, setup, and programming
Data Link References
This table identifies which serial data link that a particular module uses for in-vehicle data transmission. Some modules may use more than one data link to communicate. Some modules may have multiple communication circuits passing through them without actively communicating on that data link. This table is used to assist in correcting a communication malfunction. For the description and operation of these serial data communication circuits refer to Body Control System Description and Operation .
| Control Module | Data Link Type | Diagnostic Procedure |
|---|---|---|
| Schematic Reference: Body Control System Description and Operation | ||
| Active Front Steering (AFS) Module w/ JL7 | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Audio Amplifier | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Vehicle Communication Interface Module (OnStar) | High Speed GMLAN - pass through only Low Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device or Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Digital Radio Receiver (DRR) Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Distance Sensing Cruise Control (DSCC) Module | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Driver Door Module (DDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Driver Door Switch (DDS) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Dynamic Headlamp Leveling (DHL) Module, w/ TR7 | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Driver Position (Memory Seat) Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Electronic Brake Control Module (EBCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Electronic Suspension Control (ESC or MRRTD) Module | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Engine Control Module (ECM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Head Up Display (HUD) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Climate Control Panel (CCP) Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Instrument Panel Cluster (IPC) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Instrument Panel Module (IPM) | High Speed GMLAN Low Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device or Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Inflatable Restraint Sensing and Diagnostic Module (SDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Left Rear Door Module (LRDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Passenger Door Module (PDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Radio | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Rear Integration Module (RIM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Remote Control Door Lock Receiver (RCDLR) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Right Rear Door Module (RRDM) | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Side Blind Zone Alert (SBZA) Module, left | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Side Blind Zone Alert (SBZA) Module, right | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Steering Column Lock Control Module (SCLM), w/ UA2 | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Supervisory Control Module (SCM) w/ JL7 | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Television Tuner Module, w/ YQ6 or YQ7 | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| Transmission Control Module (TCM) | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| Vehicle Direction Alert Alarm (Lane Departure) Warning Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
Gateway
The instrument panel module (IPM) is the gateway between low speed and high speed GMLAN serial data circuits. The purpose of the gateway is to transfer serial data messages from one subnet to another. The IPM shall unpack the signals from frames received from one bus that are to be transmitted across the gateway and repack the signals into frames to be transmitted on the other bus. The IPM shall be responsible for data passing only. The data passed from one bus to the other shall in no way be modified by the IPM gateway function. The IPM receives 3 distinct types of messages on a given bus
- Signals the IPM uses for internal functional applications
- Signals the IPM uses for internal functional applications and are passed from one bus to the other bus
- Signals the IPM does not use for internal functional applications but are passed from one bus to the other bus
Power Mode
The IPM is the power mode master (PMM). Refer to Power Mode Description and Operation for more information.
Load Management
The power management function is designed to monitor the vehicle electrical load and determine when the battery is potentially in a high discharge condition. This is accomplished by using a high accuracy battery voltage and current reading by a current sensor as an indicator of battery discharge rate. The following 6 levels of load management will execute in the load management control algorithm when there is a high discharge condition
- The first action requests a vehicle idle speed increase to the engine control module (ECM) in order to raise alternator output.
- The second action requests a greater vehicle idle speed increase to the ECM in order to raise alternator output.
- The third action begins to shed vehicle loads in an attempt to remedy the heavy discharge condition.
- The fourth action requests another vehicle idle speed increase to the ECM in order to raise further the alternator output.
- The fifth action begins to shed further vehicle loads in an attempt to remedy the heavy discharge condition.
- If the above 5 corrective actions fail, the sixth action of power management further sheds loads in a final attempt to remedy the high discharge condition.
Loads subject to reduction include the following
- The A/C clutch
- The heated mirrors
- The heated seats
- The rear defog
- The HVAC blowers
- The interior lighting
For more information about load shedding, refer to Load Shed System Description and Operation .
Each load management function, either idle boost or load-shed, is discrete. No 2 functions are implemented at the same time. During each load management function, the power mode master (PMM) checks the battery temperature, battery voltage and amp-hour calculations and determines if the PMM should implement a different power management function.
Regulator Voltage Control (RVC)
Regulator voltage control (RVC) will result in the battery being charged at its optimum voltage for improved battery life and state of charge (SOC), fuel economy and lamp life by lowering the system voltage when the SOC is high. The electrical power management (EPM) algorithm in the instrument panel module (IPM) will determine the optimum charging voltage, based on estimates of its SOC and battery electrolyte temperature. Optimum charge voltage is defined as the battery charge voltage that results in maximum battery life, while maintaining energy storage for engine starting, discharge at idle, and parasitic loads. The optimum battery charge voltage will be converted to a percent duty cycle command that will be sent to the ECM via serial data link. The ECM will then place the 128 Hz pulse width modulation (PWM) duty cycle on the L line.
Other IPM Functions
The instrument panel module (IPM) performs multiple body control functions. The IPM can control devices directly connected to its outputs based on input information. The IPM evaluates this information and controls certain body control systems by commanding outputs on or off. The IPM inputs can be
- Sensors and switches that are directly connected to the IPM
- GMLAN serial data messages received from other vehicles systems connected to the low or high speed GMLAN serial data links
The IPM is also capable of controlling other vehicle systems that are not directly wired to the IPM, through serial data messages. Some of the functions that the IPM controls or contributes to, are
- Audible warnings-Refer to «Indicator/Warning Message Description and Operation»(ref-338124-S36615779072009081700000) .
- Column lock-Refer to «Steering Wheel and Column Description and Operation»(ref-338120-S15541242562009081700000) .
- Exterior lighting control and BASS-Refer to «Exterior Lighting Systems Description and Operation»(ref-338126-S20502996392009081700000) .
- Interior lighting-Refer to «Interior Lighting Systems Description and Operation»(ref-338126-S32010492552009081700000) .
- Headlamp washer-Refer to «Headlamp Washer System Description and Operation»(ref-338129-S01590369582009081700000) .
- Horn control-Refer to «Horns System Description and Operation»(ref-338155-S09357416992009081700000) .
- Park brake switch-Refer to «Park Brake System Description and Operation»(ref-338145-S02818124052009081700000) .
- Retained accessory power-Refer to «Power Mode Description and Operation»(ref-338153-S19484851432009081700000) .
- Remote start-Refer to «Starting System Description and Operation»(ref-338135-S36641686412009081700000) .
- Steering wheel control switches-Refer to «Radio/Audio System Description and Operation»(ref-338122-S19492769802009081700000) and «Cruise Control Description and Operation (Conventional Cruise Control)»(ref-338175-S41514878962009081700000) or «Cruise Control Description and Operation (Adaptive Cruise Control)»(ref-338175-S16398168252009081700000) .
- Traction control switch-Refer to «ABS Description and Operation»(ref-338158-S38897526922009081700000) .
Rear Integration Module (RIM)
The various rear integration module (RIM) inputs and outputs are described in the corresponding functional areas as indicated on the RIM electrical schematics. The RIM functions include the following
- Content theft deterrent-Refer to «Content Theft Deterrent (CTD) Description and Operation»(ref-338157-S15170027302009081700000) .
- Interior lighting-Refer to «Interior Lighting Systems Description and Operation»(ref-338126-S32010492552009081700000) .
- Exterior lighting-Refer to «Exterior Lighting Systems Description and Operation»(ref-338126-S20502996392009081700000) .
- Rear defogger-Refer to «Rear Window Defogger Description and Operation»(ref-338112-S34069310502009081700000) .
- Rear park assist chime control-Refer to «Object Detection Description and Operation (Parking Assist)»(ref-338154-S00306495062009081700000) or «Object Detection Description and Operation (Lane Departure Warning)»(ref-338154-S01161198862009081700000) or «Object Detection Description and Operation (Side Blind Zone Alert)»(ref-338154-S40689673102009081700000) .
- Sunroof control-Refer to «Sunroof Description and Operation»(ref-338159-S03614363222009081700000) .
Data Link Connector (DLC)
The data link connector (DLC) is a standardized 16-cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following
- Scan tool power battery positive voltage at terminal 16
- Scan tool power ground at terminal 4
- Common signal ground at terminal 5
- Low speed GMLAN serial data bus at terminal 1
- High speed GMLAN serial data bus (+) at terminal 6
- High speed GMLAN serial data bus (-) at terminal 14
High Speed GMLAN Serial Data Line
The GMLAN serial data communications circuit on this vehicle is in a linear topology. The following modules are connected to the link, in order from data link connector (DLC) to the end of the linear configuration
- The instrument panel module (IPM)
- The electronic suspension control (ESC) module, with F85
- The communication interface module (OnStar), with UE1
- The dynamic headlamp leveling (DHL) device, with TR7
- The electronic brake control module (EBCM)
- The transmission control module (TCM)
- The engine control module (ECM)
The distance sensing and cruise control (DSCC) module, with K59 option, it is connected to the high speed GMLAN bus through splice pack SP100. Refer to Data Communication Schematics for more information.
The OnStar module doesn't functionally communicate on the high speed GMLAN bus. It is connected to high speed GMLAN bus for remotely diagnostic purposes.
Low Speed GMLAN Serial Data Line
The low speed GMLAN serial data communication circuit on this vehicle is in a star configuration. The star has 3 splice packs, located as follows
- The splice pack SP201 is located under the left side of the instrument panel (I/P), near the data link connector (DLC).
- The splice pack SP300 is located next by the left B-pillar.
- The splice pack SP303 is located next by the right B-pillar.
The following modules communicate on the low speed GMLAN serial data circuit
- The splice pack SP201 attaches to: The instrument panel module (IPM) The head-up display (HUD), with UV6 The HVAC control module The instrument panel cluster (IPC) The radio The steering column lock control module (SCLCM), with UA2
- The splice pack SP300 attaches to: The audio amplifier The driver door module (DDM) The driver door switch (DDS) is attached to DDM The driver position module (DPM), with A45 The digital radio receiver (DRR), with U2K The inflatable restraint sensing and diagnostic module (SDM) The left rear door module (LRDM) The rear integration module (RIM) The remote control lock door receiver (RCDLR) The television (TV) module, with YK6/YK7
- The splice pack SP303 attaches to: The communication interface module (OnStar), with UE1 The inflatable restraint SDM The passenger door module (PDM) The right rear door module (RRDM)
Refer to Data Communication Schematics for more information.