U1511
DTC U1500, U1511, U1512, or U1513
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC U1500 01
- Inter-Device Dedicated Bus 1 Short to Battery
DTC U1500 02
- Inter-Device Dedicated Bus 1 Short to Ground
DTC U1511 00
- Inter-device Dedicated Bus Lost Communication With Device 1
DTC U1512 00
- Inter-device Dedicated Bus Lost Communication With Device 2
Diagnostic Fault Information
Circuit/System Description
The driver door module (DDM) and the front passenger door module (FPDM) communicate with window regulator motors on the local interconnect network bus 1 and the local interconnect network bus 2 circuits respectively. The DDM LIN bus is connected to all window regulator motors on its side of the vehicle, while the FPDM LIN bus is connected to the other window regulator motors. Communication on this network is only between the door modules and the window regulator motors. The window regulator motors are in effect modules. The window regulator motors do not communicate on any other data bus, therefore the door modules, which also communicate on the low speed GMLAN serial data bus will perform all communication with each other. If the driver depresses any passenger side window switch on the driver window switch the DDM communicates the information to the FPDM for operation. These DTCs will set in the DDM for driver side concerns or the FPDM for passenger side concerns.
Conditions for Running the DTC
The system voltage is between 9-16 volts.
Conditions for Setting the DTC
U1511
* The local interconnect network bus circuit of the front window motor has an open/high resistance.
* The B+ circuit of the front window motor is open or shorted to ground.
* The ground circuit of the front window motor is open.
U1512
* The local interconnect network bus circuit of the rear window motor has an open/high resistance.
* The B+ circuit of the rear window motor is open or shorted to ground.
* The ground circuit of the rear window motor is open.
U1500 02
The local interconnect network bus circuit is a shorted to ground.
U1500 01
The local interconnect network bus circuit is a shorted to voltage.
Action Taken When the DTC Sets
U1511
The rear window will operate.
U1512
The front window will operate.
U1500
The individual LIN bus will be inoperative, causing all windows on one side of the vehicle to be inoperative.
Conditions for Clearing the DTC
* The current DTC will clear when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
Diagnostic Aids
* Both DTC U1511 and U1512 will set if an open/high resistance in the local interconnect network bus circuit is between the door module and the first splice.
* Only 1 DTC (U1511 or U1512) will set if an open/high resistance in the local interconnect network bus circuit is between the splice and the window motor.
Reference Information
Schematic Reference
* Data Communication Schematics (Electrical Diagrams)
* Moveable Window Schematics (Electrical Diagrams)
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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate window motor.
2. Test for less than 2.0 ohms between the ground circuit terminal 4 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Test for 5.5-7.0 volts between the LIN circuit terminal 6 and ground.
• If greater than the specified range, test the LIN circuit for a short to voltage. If the circuit tests normal, replace the applicable door module.
• If less than the specified range, test the LIN circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the applicable door module.
5. Ignition OFF, reconnect the harness connector at the window motor.
6. Ignition ON, observe the appropriate scan tool Front Window Motor Fault Status parameter while attempting to raise and lower the window. The parameter should read No Fault.
• If the parameter displays Not Normalized, refer to Control Module References (Programming and Relearning) for programming the window motors.
• If the parameter reads Motor Fault, Hall Fault, Memory Fault, LIN Fault, Anti-Trap Fault or Thermo Active, replace the appropriate power window motor.
7. If all circuits test normal, replace the appropriate door module.
Repair Instructions
Important: Each window regulator motor or front window and door lock switch, if replaced needs to be setup for proper operation.
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning) for window, and door lock switch (door module) or window regulator motor replacement, setup, and programming