Engine-CodesGMC – U1147 GMC

U1147 GMC Code - Lost Communication With Onstar

Quick Answer

The U1147 code for GMC vehicles indicates that there has been a communication failure with the OnStar system. Common causes include Faulty OnStar module, Wiring issues, Blown fuse. 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
U1147 GMC indicates Lost Communication With Onstar.
Common causes
Common causes include Faulty OnStar module, Wiring issues, Blown fuse.
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.
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code U1147 GMC Description

The U1147 code for GMC vehicles indicates that there has been a communication failure with the OnStar system. OnStar is a subscription-based service that provides a variety of features such as emergency assistance, navigation, and remote vehicle diagnostics. When this code is triggered, it means that the vehicle's onboard computer is no longer able to communicate effectively with the OnStar system.

OBDII Code U1147 GMC - Lost Communication With Onstar
U1147 GMC Code - Lost Communication With Onstar

Common Causes of U1147 GMC

  1. Faulty OnStar module
  2. Wiring issues
  3. Blown fuse
  4. Malfunctioning control module
  5. Software glitch in the communication system

Symptoms of U1147 GMC

  1. OnStar services not functioning properly
  2. Loss of GPS navigation functionality
  3. Warning light on the dashboard related to communication system
  4. Inability to remotely access vehicle features through the OnStar app

How to Fix U1147 GMC

  1. Begin by checking the OnStar module for any visible damage or loose connections. Replace the module if necessary.
  2. Inspect the wiring harness for any signs of wear, corrosion, or damage. Repair or replace any damaged wiring.
  3. Check and replace any blown fuses related to the communication system.
  4. Use a diagnostic tool to scan for any error codes and reset the communication system.
  5. If the issue persists, consult with a professional technician for further diagnosis and repair.

Cost to Fix U1147 GMC

The cost of repairing a U1147 code related to lost communication with OnStar can vary depending on the specific cause of the issue. On average, the parts and labor for this repair could range from $100 to $500. However, it's important to note that diagnostic time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's recommended to obtain quotes from multiple shops to get a more accurate estimate.

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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 U1147 GMC Code

1. What are the common symptoms of OBDII code U1147 GMC (Lost Communication With Onstar)?

- Common symptoms include the Onstar system not functioning properly, a loss of communication with Onstar services, and potential issues with vehicle diagnostics.

2. What are the possible causes of OBDII code U1147 GMC?

- The code U1147 GMC is typically triggered by a malfunction in the Onstar module, faulty wiring or connections related to the Onstar system, or an issue with the vehicle's communication network.

3. How can I diagnose the cause of OBDII code U1147 GMC?

- Diagnosis involves checking the Onstar module for proper functioning, inspecting wiring and connections for any damage or loose connections, and using a diagnostic scanner to assess the communication network.

4. Can I still drive my vehicle with OBDII code U1147 GMC?

- While the vehicle may still be drivable with this code, it is recommended to address the issue promptly to ensure the Onstar system functions correctly and to prevent any potential underlying communication network problems.

5. How can I repair OBDII code U1147 GMC?

- Repair options include checking and repairing any damaged wiring or connections, replacing the Onstar module if necessary, and resetting the code using a diagnostic scanner after the repairs have been made.

6. Are there any DIY tips for troubleshooting OBDII code U1147 GMC?

- DIY tips include visually inspecting wiring and connections for any obvious issues, checking fuses related to the Onstar system, and ensuring the vehicle's battery is in good condition.

7. Will resetting the OBDII code U1147 GMC resolve the issue?

- Resetting the code is a temporary solution and may not address the underlying problem causing the communication loss with Onstar. It is important to diagnose and repair the root cause of the issue.

8. Can a dealership or mechanic help with fixing OBDII code U1147 GMC?

- Yes, a dealership or qualified mechanic with experience in diagnosing and repairing Onstar system issues can assist in resolving OBDII code U1147 GMC.

9. Is OBDII code U1147 GMC a serious issue?

- While the code itself may not directly affect the drivability of the vehicle, it is important to address it promptly to ensure the proper functioning of the Onstar system and to prevent potential communication network problems.

10. How can I prevent OBDII code U1147 GMC from occurring in the future?

- Regularly checking the Onstar system for any signs of malfunction, keeping wiring and connections well-maintained, and addressing any related issues promptly can help prevent the recurrence of code U1147 GMC.

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