2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2039
Circuit/System Verification
1. Engine running for 10 seconds.
2. Ignition ON, engine OFF, verify the DTC U0400-U05FF is not set.
瀚慖f the DTC U0400-U05FF is set along with other DTCs set, diagnose all other codes first. Refer to Diagnostic Trouble Code (DTC) List -
Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
瀚慖f the DTC U0400-U05FF is set without other DTCs set, program the control module specified by the DTC descriptor. If the DTC resets,
replace the appropriate control module.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for control module replacement, setup, and programming
U1500
DTC U1500-U15BF
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
Refer to Control Module U Code List (See: Diagnostic Trouble Code Descriptions/Control Module U Code List).
Circuit/System Description
The serial data is transmitted over a Local Interconnect Network (LIN) single wire network circuit bus between a master control module and other
control modules within a particular subsystem. If serial data communication is lost between any of the control modules on the LIN bus network, a
no communication code against the non-communicating control module will be set. A master control module is the one that reports the non
communication code. Note: a loss of serial data communications DTC does not represent a failure of the master control module that set it.
Diagnostic Aids
* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between
control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a
control module based only on a history U-code.
* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication
issue.
* Communication will be available between the master control module and the scan tool if there is a loss of communications with any of the
other control modules on the LIN bus network.
* An open in the LIN bus serial data circuit between the splice pack and a module will only affect that specific module. This type of failure will
set a loss of communication DTC for each control module affected and the other control modules will still communicate.
Reference Information
Schematic Reference
Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
Description and Operation
Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information
Bus/Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
