2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2046
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
DTC U2103 00
- Fewer Controllers On Than Programmed
Circuit Description
Modules connected to the 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 programmed information about what messages are needed to be
exchanged on the serial data circuits, for each virtual network. The messages are also supervised and some periodic messages are used by the
receiver module as an availability indication of the transmitter module.
DTC U2103 will set when fewer modules are detected on the buss before the modules can learn the other module IDs. If the communication buss is
opened, or if the module power supply is lost when the vehicle is in the OFF power mode, and then placed in the RUN power mode, U2103 will set
in specific modules.
Conditions for Running the DTCs
* Voltage supplied to the modules is in the normal operating voltage range.
* The vehicle power mode requires serial data communication to occur.
* The DTC U2100 does not have a current status.
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 parameter.
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.
Diagnostic Aids
* Diagnosis of this DTC is accomplished via the symptom or an additional DTC. Refer to Symptoms - Data Communications (See:
Powertrain Management/Computers and Control Systems/Information Bus/Testing and Inspection/Symptom Related Diagnostic
Procedures/Symptoms - Data Communications) or DTC U0100-U02FF (See: U Code Charts/U0100).
* An intermittent condition is likely to be caused by a short on the GMLAN serial data circuits. Use the DTC U0100-U02FF (See: U Code
Charts/U0100) procedure in order to isolate an intermittent condition.
U2105
DTC U2105-U2199
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using the 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.
Diagnostic Fault Information
