2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2023

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 2023

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 control module for a short to ground. If the circuits test normal, replace the control module.

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 control module for a short to ground. If the circuits test normal, replace the control module.

Note: Only the high speed GMLAN modules have a serial data communication enable circuit OR an accessory wake-up serial data circuit,

and the BCM is the output for these circuits. Refer to the control module schematics to identify which modules have these circuits.

5. If equipped, ignition ON, verify that a test lamp illuminates between the communication enable circuit terminal OR the accessory wake-up

circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the entire circuit, including the B+ circuit to the BCM, for an open/high resistance or short to

ground. If the circuits test normal, replace the BCM.

6. Ignition OFF for 60 seconds, test for less than 5 ohm between the serial data circuit terminals and the appropriate DLC terminal listed below:

* Class 2 serial data circuit terminal 2

* Low speed GMLAN serial data terminal 1

* High speed GMLAN serial data terminal 6 or 14

瀚慖f greater than the specified range, test the serial data circuit for an open/high resistance between the non communicating control module

and a module setting the DTC or a serial data splice pack.

7. If all circuits test normal, replace the control module that is not communicating.

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/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

U05FF

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