2010 Cadillac Truck SRX FWD V6-3.0L Page 2165

2010 Cadillac Truck SRX FWD V6-3.0L Page 2165

that was just disconnected.

瀚慖f the test lamp does illuminate, test the ignition circuit for a short to voltage. If the circuits test normal, replace the control module that

was just disconnected.

3. Ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.

瀚慖f the circuits test normal, replace the control module that was just disconnected.

4. Connect the harness connectors at the control module that was just disconnected.

5. Repeat step 1 at another control module until a short to voltage, a short to ground, or an open/high resistance is found on the ignition circuits.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the repair.

* GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Wiring Repairs/GMLAN Wiring Repairs)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for control module replacement, programming and

setup

U0100

DTC U0100-U02FF

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).

Diagnostic Fault Information

Circuit/System Description

The serial data circuit is the means by which the control modules in the vehicle communicate with each other. Once the scan tool is connected to the

serial data circuit through the data link connector (DLC), the scan tool can be used to monitor each control module for diagnostic purposes and to

check for diagnostic trouble codes (DTCs). When the ignition switch is in RUN, each control module communicating on the serial data circuit

sends a state of health (SOH) message to ensure that the control module is operating properly. When a control module stops communicating on the

serial data circuit, for example if the control module loses power or ground, the SOH message it normally sends on the serial data circuit

disappears. Other control modules on the serial data circuit, which expect to receive that SOH message, detect its absence; those control modules in

turn set a DTC associated with the loss of SOH of the non-communicating control module. The DTC is unique to the control module which is not

communicating and one or more control modules may set the same exact code. A loss of serial data communications DTC does not represent a

failure of the control modules that contain the stored code.

Conditions for Running the DTC