2010 Cadillac CTS Sedan AWD V6-3.0L Page 2034
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/GMLAN Wiring Repairs)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for control module replacement, setup, and
programming
U0400
DTC U0400-U05FF
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
Some control modules are constantly receiving information from other control modules through serial data communication network. The invalid
data code will be set when a receiving control module detects a discrepancy in information it receives from another control module causing its
integrity to be questioned. The symptom byte listed in the DTC Descriptor is for engineering reference only. No external circuit diagnosis is
involved.
Conditions for Running the DTC
Battery voltage is between 9-16 V and data link communications operate normally.
Conditions for Setting the DTC
The control module is not configured properly.
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, without a repeat of the malfunction.
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)
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/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool References
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
