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Engine-Codes – GMC – U1793 GMC

U1793 GMC Code - 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus

Quick Answer

The U1793 diagnostic trouble code (DTC) for GMC vehicles indicates that the 14V Power Module has lost communication with the Hybrid/EV Powertrain Control Module on the Powertrain Expansion Communication Bus. Common causes include Loose or damaged wiring connections between the Power Module and Powertrain Control Module, Faulty communication modules or components, Software glitches or programming errors. 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
U1793 GMC indicates 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus.
Common causes
Common causes include Loose or damaged wiring connections between the Power Module and Powertrain Control Module, Faulty communication modules or components, Software glitches or programming errors.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code U1793 GMC Description

The U1793 diagnostic trouble code (DTC) for GMC vehicles indicates that the 14V Power Module has lost communication with the Hybrid/EV Powertrain Control Module on the Powertrain Expansion Communication Bus. In hybrid or electric vehicles, the Power Module is responsible for managing the high voltage power supply to various components, while the Powertrain Control Module controls the operation of the hybrid or electric powertrain system. When communication is lost between these modules, it can lead to a range of issues affecting the vehicle's performance and efficiency.

OBDII Code U1793 GMC - 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus
U1793 GMC Code - 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus

Common Causes of U1793 GMC

  1. Loose or damaged wiring connections between the Power Module and Powertrain Control Module
  2. Faulty communication modules or components
  3. Software glitches or programming errors
  4. Issues with the high voltage power supply to the modules
  5. Environmental factors such as moisture or corrosion affecting the communication bus

Symptoms of U1793 GMC

  1. Check engine light illuminated on the dashboard
  2. Loss of hybrid or electric powertrain functionality
  3. Reduced fuel efficiency
  4. Erratic performance or drivability issues
  5. Potential safety warnings or messages on the instrument cluster

How to Fix U1793 GMC

  1. Perform a thorough diagnostic scan to retrieve the U1793 code and identify the specific modules involved in the communication failure.
  2. Inspect wiring connections between the Power Module and Powertrain Control Module for any signs of damage, corrosion, or looseness. Repair or replace as necessary.
  3. Check the communication modules for faults or malfunctions, and replace if needed.
  4. Update software or reprogram the modules to ensure proper communication and functionality.
  5. Test drive the vehicle to verify that the issue has been resolved and clear the DTC from the vehicle's memory.

Cost to Fix U1793 GMC

The typical repair costs for addressing the U1793 DTC can vary depending on the specific cause of the communication failure and the extent of the repairs needed. In general, the cost of parts and labor for this issue can range from $200 to $500 or more. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's recommended to check with local shops for a more accurate estimate based on your vehicle make and model. Labor rates typically range from $80 to $150 per hour, with rates potentially higher at dealerships or in metropolitan areas. Independent shops may offer more competitive pricing for the repair.

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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 U1793 GMC Code

1. What are the common symptoms of OBDII code U1793 in a GMC vehicle?

- Common symptoms include loss of power, issues with starting the vehicle, poor fuel efficiency, and warning lights on the dashboard.

2. What does the OBDII code U1793 indicating "14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus" mean?

- This code indicates a communication problem between the 14V power module and the Hybrid/EV powertrain control module on the vehicle's communication bus.

3. What are some possible causes of OBDII code U1793 in a GMC vehicle?

- Possible causes include damaged wiring, loose connections, faulty power modules, issues with the control modules, or problems with the communication bus.

4. How can I diagnose the OBDII code U1793 in my GMC vehicle?

- Diagnosing this code typically involves using a diagnostic scanner to retrieve the specific trouble codes, checking the wiring and connections related to the power modules and control modules, and testing the communication bus for faults.

5. How serious is OBDII code U1793 in a GMC vehicle?

- This code should be addressed promptly as it can lead to performance issues and potential safety concerns if left unresolved.

6. Can I continue driving my GMC vehicle with OBDII code U1793 present?

- It is not recommended to drive the vehicle with this code active, as it may affect the vehicle's performance and safety systems.

7. How can I repair OBDII code U1793 in my GMC vehicle?

- Repairing this code may involve fixing any wiring or connection issues, replacing faulty power modules or control modules, and ensuring proper communication between the components.

8. Is it necessary to visit a mechanic for OBDII code U1793 repair?

- While some DIY enthusiasts may attempt to diagnose and repair this code themselves, consulting a qualified mechanic is recommended for a thorough and accurate repair.

9. Are there any specific models of GMC vehicles prone to experiencing OBDII code U1793?

- This code can potentially occur in various GMC models equipped with hybrid or electric powertrain components that communicate over the powertrain expansion communication bus.

10. How can I prevent OBDII code U1793 from occurring in my GMC vehicle?

- Regular maintenance, such as checking and maintaining wiring connections, monitoring the health of power modules and control modules, and addressing any warning signs promptly, can help prevent the occurrence of this code.

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