AutoCodes – GMC – U1040 GMC

U1040 GMC Code - Lost Communication With Electronic Brake Control Module

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Electronic Brake Control Module, Electronic Brake Control Module harness is open or shorted, Electronic Brake Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U1040 GMC indicates Lost Communication With Electronic Brake Control Module.
Common causes: Common causes include Faulty Electronic Brake Control Module, Electronic Brake Control Module harness is open or shorted, Electronic Brake Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,540

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1040 GMC Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1040 is set.

OBDII Code U1040 GMC - Lost Communication With Electronic Brake Control Module - AutoCodes.com — U1040 GMC Code - Lost Communication With Electronic Brake Control Module

What does this mean?

What are the Possible Causes of the DTC U1040 GMC?

Faulty Electronic Brake Control Module
Electronic Brake Control Module harness is open or shorted
Electronic Brake Control Module circuit poor electrical connection

How to Fix the DTC U1040 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1040 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U1040 GMC Code

1. What are the common symptoms of OBDII code U1040 GMC (Lost Communication With Electronic Brake Control Module)?

The common symptoms include the ABS warning light coming on, traction control issues, and potential loss of communication with the brake system.

2. What are some possible causes of OBDII code U1040 GMC?

Possible causes include a faulty electronic brake control module, damaged wiring or connectors, a blown fuse, or a communication bus issue within the vehicle's network.

3. How can I diagnose the cause of OBDII code U1040 GMC?

Diagnosing the issue typically involves checking the wiring and connectors for damage, verifying the fuse for the electronic brake control module, and using a diagnostic scan tool to assess communication with the module.

4. Can driving with OBDII code U1040 GMC pose any risks?

Continuing to drive with this code present can potentially affect the vehicle's braking system and traction control, leading to safety concerns. It's recommended to address the issue promptly.

5. How can I repair OBDII code U1040 GMC?

Repairing the code usually involves fixing any damaged wiring or connectors, replacing the electronic brake control module if necessary, ensuring proper power supply to the module, and clearing the code with a diagnostic tool.

6. Is it possible to prevent OBDII code U1040 GMC from occurring?

Regularly inspecting the vehicle's wiring, connectors, and fuses, as well as addressing any warning lights promptly, can help prevent this code from occurring due to communication issues with the electronic brake control module.

7. Can a DIY enthusiast fix OBDII code U1040 GMC?

Depending on their skill level and access to tools, a DIY enthusiast may be able to address this code by checking and repairing wiring, connectors, or fuses. However, complex electronic issues may require professional assistance.

8. Are there any software updates available to address OBDII code U1040 GMC?

In some cases, a software update from GMC may be available to resolve communication issues with the electronic brake control module. Checking with a dealership or authorized service center is recommended.

9. Will disconnecting the battery reset OBDII code U1040 GMC?

Disconnecting the battery may reset the code temporarily, but if the underlying issue causing the lost communication with the electronic brake control module is not addressed, the code is likely to reappear.

10. How urgent is it to address OBDII code U1040 GMC?

It's important to address this code promptly to ensure the proper functioning of the vehicle's braking system and traction control. Ignoring the issue could lead to potential safety risks while driving.