2010 Cadillac Truck SRX FWD V6-3.0L Page 2176
DTC Descriptor
DTC U2099 00
- High Speed Communication Enable Circuit
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) activates the serial data communication enable circuit, when the ignition key is in ACC, ON or START. The serial
data communication enable circuit wakes up the modules for serial data buss communication.
Conditions for Running the DTC
* The system voltage is between 9-16 volts.
* The vehicle power mode master requires serial data communication to occur.
Conditions for Setting the DTC
The BCM senses a short to ground on the serial data communication enable circuit.
Action Taken When the DTC Sets
* The output command is turned off while the malfunction is present.
* The modules use a default value for the missing parameters until the next ignition cycle.
* The module(s) is never signaled, therefore the specific subsystem(s) will not function.
* The vehicle will not start while the circuit is shorted to ground.
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 DMM MIN/MAX function to capture/locate intermittent conditions.
* Short to ground will also set multiple history no communication codes for GMLAN high speed modules.
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
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Circuit/System Testing
