2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2040

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2040

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

Note:

* Use the schematic to identify the following:

- Control modules and LIN devices the vehicle is equipped with

- Control module and LIN device locations on the serial data circuit

- The control module serial data circuit terminals and LIN device B+, ignition, ground, and serial data circuit terminals

* Use the Control Module U-Code list to determine which control module is not communicating with the master control module. Refer to

Control Module U Code List (See: Diagnostic Trouble Code Descriptions/Control Module U Code List).

* A loss of serial data communications DTC does not represent a failure of the master control module that set it.

1. Ignition OFF, disconnect the harness connector at a LIN device that is not communicating.

2. Test for less than 5 ohm between each ground circuit terminal and ground.

瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.

3. If equipped, verify that a test lamp illuminates between each B+ circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the

control circuits of the LIN device for a short to ground. If the circuits test normal, replace the LIN device.

4. If equipped, ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test

the control circuits of the LIN device for a short to ground. If the circuits test normal, replace the LIN device.

5. Ignition ON, test for 2-11.5 V between the LIN serial data circuit and ground.

瀚慖f greater than the specified range, test the LIN serial data circuit for a short to voltage. If the circuit tests normal, replace the master

control module.

瀚慖f less than the specified range, test the LIN serial data circuit for a short to ground or an open/high resistance. If the circuit tests normal,

replace the master control module.

6. If all circuits test normal, replace the LIN device.

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, setup, and

programming

U1814

DTC U1814

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

DTC U1814 00

- Powertrain Wake Up Communication Circuit