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U2130




DTC U2105-U2199

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using the diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptors
DTC U2105 00
- Lost Communication With Engine Control System

DTC U2106 00
- Lost Communication With Transmission Control System

DTC U2107 00
- Lost Communication With Body Control System

DTC U2108 00
- Lost Communication With ABS/TCS Control System

DTC U2109 00
- Lost Communication With Powertrain Control System

DTC U2110 00
- Lost Communication With Chassis Multiple Control System

DTC U2111 00
- Lost Communication With Steering Control System

DTC U2112 00
- Lost Communication With Electronic Suspension Control (ESC)

DTC U2113 00
- Lost Communication With Sensing and Diagnostic Module (SDM)

DTC U2114 00
- Lost Communication With PPS or CPS

DTC U2115 00
- Lost Communication With (Restraints Control System)

DTC U2116 00
- Lost Communication With Instrument Panel Cluster (IPC)

DTC U2117 00
- Lost Communication With Driver Information Center (DIC)

DTC U2118 00
- Lost Communication With Head Up Display (HUD)

DTC U2119 00
- Lost Communication With Daytime Running Lamps (DRL) System

DTC U2120 00
- Lost Communication With Automatic Headlamp Leveling Device (AHLD)

DTC U2121 00
- Lost Communication With Radio Display

DTC U2122 00
- Lost Communication With Radio

DTC U2123 00
- Lost Communication With Compact Disc Changer (CDX)

DTC U2124 00
- Lost Communication With Audio Amplifier

DTC U2125 00
- Lost Communication With Telematic Unit

DTC U2126 00
- Lost Communication With (Mobile Communications Control System)

DTC U2127 00
- Lost Communication With Front HVAC

DTC U2128 00
- Lost Communication With Rear HVAC

DTC U2129 00
- Lost Communication With Remote Function Actuator (RFA)

DTC U2130 00
- Lost Communication With Driver Door Module (DDM)

DTC U2131 00
- Lost Communication With Driver Seat Module (DSM)

DTC U2132 00
- Lost Communication With Passenger Door Module (PDM)

DTC U2133 00
- Lost Communication With Passenger Seat Module (PSM)

DTC U2134 00
- Lost Communication With Rear Door Module (RDM)

DTC U2135 00
- Lost Communication With Rear Integration Module (RIM)

DTC U2136 00
- Lost Communication With Memory Mirror Module (MMM)

DTC U2137 00
- Lost Communication With Vehicle Theft Deterrent (VTD)

DTC U2138 00
- Lost Communication With Column Locking Module (CLM)

DTC U2139 00
- Lost Communication With Column Integration Module (CIM)

DTC U2140 00
- Lost Communication With Underhood Electrical Center (UEC)

DTC U2141 00
- Lost Communication With Rear Electrical Center (REC)

DTC U2142 00
- Lost Communication With Yaw Rate Sensor (YRS)

DTC U2143 00
- Lost Communication With Steering Angle Sensor (SAS)

DTC U2144 00
- Lost Communication With Distance Sensing Cruise Control Module

DTC U2145 00
- Lost Communication With Parking Assistance System (PAS)

DTC U2146 00
- Lost Communication With Shift Lever Module (SLM)

DTC U2147 00
- Lost Communication With Auxiliary Heater System (AHS)

DTC U2148 00
- Lost Communication With Sun Roof Module (SRM)

DTC U2149 00
- Lost Communication With Tire Pressure Monitor (TPM) System

DTC U2150 00
- Navigation Electronic Control Unit (ECU) Gateway Communications

DTC U2151 00
- Navigation Electronic Control Unit (ECU) Communications

DTC U2152 00
- Navigation Bus Request Line Circuit Low

DTC U2153 00
- Navigation Electronic Control Unit (ECU) - VICS Communication Circuit

DTC U2160 00
- Lost Communication With Steering Control System Sensor

DTC U2161 00
- Lost Communication With Dash Integration Module (DIM)

DTC U2162 00
- Lost Communication With Instrument Panel integration Module (IPM)

DTC U2163 00
- Lost Communication With Left Rear Door Module (LRDM)

DTC U2164 00
- Lost Communication With Right Rear Door Module (RRDM)

DTC U2165 00
- Lost Communication With Driver Door Switch (DDS)

DTC U2166 00
- Lost Communication With Driver Position Module (DPM)

DTC U2167 00
- Lost Communication With Remote Control Door Lock Receiver

DTC U2168 00
- Lost Communication With Side Object Detection (SOD) Module - Left

DTC U2169 00
- Lost Communication With Side Object Detection (SOD) Module - Right

DTC U2170 00
- Lost Communication With Four Wheel Drive (4WD) Clutch

DTC U2171 00
- Lost Communication With Rear Seat Entertainment (RSE)

DTC U2172 00
- Lost Communication With Digital Radio Receiver

DTC U2173 00
- Lost Communication With Passive Entry and Passive Start System

DTC U2174 00
- Lost Communication With Parking Heater System

DTC U2175 00
- Lost Communication With Special Vehicle Module

DTC U2176 00
- Lost Communication With Power Take Off (PTO) Control Module

DTC U2177 00
- Lost Communication With Cruise Control Module

DTC U2178 00
- Lost Communication With Trailer Interface Module

DTC U2179 00
- Lost Communication With Television Module

DTC U2180 00
- Lost Communication With Folding Top Control Module

DTC U2181 00
- Lost Communication With Moveable Roof Module

Diagnostic Fault Information





Circuit/System Description

Modules connected to the high and low speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The body control module (BCM) activates the high speed GMLAN serial data wake up and the accessory wake up serial data circuits by applying voltage when the ignition key is in ACC, ON or START. The high speed GMLAN serial data wake up circuit wakes up the electronic brake control module (EBCM) for bus communication and the accessory wake up serial data circuit wakes up the engine control module (ECM) and transmission control module (TCM).

Conditions for Running the DTC

* The system voltage is between 9-16 volts.
* The vehicle power mode requires serial data communication to occur.

Conditions for Setting the DTC

A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTC Sets

The module uses a default value for the missing parameters.

Conditions for Clearing the DTC

* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Diagnostic Aids

* Use the DTC Descriptor list above to determine the module which is not communicating.
* If there are multiple non-communicating modules choose the one closest to the data link connector (DLC).
* Use Data Link References (Data Link References) to determine if the module uses high or low speed GMLAN serial data communications
* Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
* This diagnostic can be used for any module that should communicate with high or low speed GMLAN serial data providing the vehicle is equipped with the option that uses that module.

Reference Information

* Data Communication Schematics (Electrical Diagrams)
* Control Module References (Programming and Relearning)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Data Link Communications Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool References

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

Important: If more than one module is not communicating use Data Communication Schematics (Electrical Diagrams) to determine which module is closest to the DLC. Start diagnostics with that module.


Terminal and connector identifiers will be different depending on the individual module being tested. Use Schematic Reference and Connector End View Reference to determine which connector and terminal to access.


1. Using the DTC Descriptor and Diagnostic Aids, determine the module that is not communicating that should be tested.
2. Ignition OFF, disconnect the harness connector of the module that is not communicating.
3. Test for less than 2 ohms between the module ground circuits and ground.

If greater than specified range, test the ground circuit for an open/high resistance.

Important: Only the high speed GMLAN modules have a wired serial data wake up circuit. Refer to the module schematics to identify which modules have a wake up circuit. If the module that is not communicating does not have a serial data wake up circuit, proceed to step 5.


4. Ignition ON, verify that a test lamp illuminates between the high speed GMLAN serial data wake up circuit OR the accessory wake up serial data circuit and ground.

If the test lamp does not illuminate, test the circuit for an open/high resistance. If the circuits test normal, replace the BCM.

5. Ignition ON, verify that a test lamp illuminates between all B+ circuits and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the appropriate module.

6. Verify that a test lamp illuminates between all ignition voltage circuits and ground.

If the test lamp does not illuminate, test the ignition voltage circuits for a short to ground or an open/high resistance. If the circuit fuse is open, also test the positive voltage outputs of the module for a short to ground. If the circuits test normal, replace the appropriate module.

7. Test for less than 1 ohm in the GMLAN serial data circuits between the non-communicating module and the module that displays the DTC.

If greater than specified range, test the GMLAN serial data circuits for open/high resistance.

8. If all circuits test normal, replace the module that is not communicating.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* GMLAN Wiring Repairs (Component Tests and General Diagnostics)
* Control Module References (Programming and Relearning) for module replacement, setup, and programming