Engine-CodesGeneric – U1793

U1793 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) 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 Faulty wiring or connectors, Malfunctioning 14V Power Module or Hybrid/EV Powertrain Control Module, Software glitches in the control modules. 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 indicates 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus.
Common causes
Common causes include Faulty wiring or connectors, Malfunctioning 14V Power Module or Hybrid/EV Powertrain Control Module, Software glitches in the control modules.
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 11, 2024
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Code U1793 Description

The U1793 diagnostic trouble code (DTC) indicates that the 14V Power Module has lost communication with the Hybrid/EV Powertrain Control Module on the Powertrain Expansion Communication Bus. In hybrid and electric vehicles, the powertrain control module plays a crucial role in managing and coordinating the operation of the various components that make up the hybrid or electric powertrain system. The 14V Power Module, on the other hand, is responsible for regulating and distributing power to various systems and components within the vehicle.

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

Common Causes of U1793

  1. Faulty wiring or connectors
  2. Malfunctioning 14V Power Module or Hybrid/EV Powertrain Control Module
  3. Software glitches in the control modules
  4. Communication network issues within the vehicle's electrical system
  5. Physical damage to the modules due to water intrusion or other environmental factors

Symptoms of U1793

  1. Loss of power or acceleration
  2. Poor fuel efficiency
  3. Illumination of the check engine light
  4. Erratic behavior of the hybrid or electric powertrain system
  5. Difficulty starting the vehicle

How to Fix U1793

  1. Perform a thorough inspection of the wiring and connectors associated with the 14V Power Module and Hybrid/EV Powertrain Control Module.
  2. Check for any software updates or reprogramming that may be available for the control modules.
  3. Test the communication network within the vehicle's electrical system to identify any issues.
  4. Replace any faulty wiring, connectors, or modules as needed.
  5. Clear the DTC and perform a test drive to ensure the issue has been resolved.

Cost to Fix U1793

The cost of repairing the U1793 code can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the typical repair costs for this type of issue can range from $200 to $500, including parts and labor. However, it's important to note that diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It is advisable to check with local auto repair shops for a more accurate estimate.

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Code U1793 Information for Specific Makes

  • U1793 Buick — 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus
  • U1793 Cadillac — 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus
  • U1793 Chevrolet — 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus
  • U1793 GMC — 14V Power Module Lost Communication With Hybrid/EV Powertrain Control Module On Powertrain Expansion Communication Bus
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 Code

What does the OBDII code U1793 mean?

The U1793 code indicates that the 14V Power Module has lost communication with the Hybrid/EV Powertrain Control Module on the Powertrain Expansion Communication Bus.

What are the common symptoms of a U1793 code?

Symptoms may include warning lights on the dashboard, limited or no hybrid/EV functionality, reduced vehicle performance, or failure to charge the battery properly.

What causes the U1793 code to appear?

Common causes include damaged or corroded wiring, faulty connectors, a malfunctioning 14V Power Module, a defective Hybrid/EV Powertrain Control Module, or a software issue.

Can a U1793 code cause drivability issues?

Yes, it can lead to reduced performance, limited hybrid/EV functionality, or a failure in certain electrical systems.

How do you diagnose a U1793 code?

Diagnosis typically involves scanning for related codes, inspecting wiring and connectors on the communication bus, and testing the 14V Power Module and Hybrid/EV Powertrain Control Module for proper operation.

Can a U1793 code clear itself?

No, the code is unlikely to clear itself and will typically require diagnosis and repair to resolve the underlying issue.

Is the U1793 code specific to certain vehicles?

Yes, it is generally found in hybrid or electric vehicles equipped with a 14V Power Module and a Hybrid/EV Powertrain Control Module.

How can you fix a U1793 code?

Repairs may include fixing or replacing damaged wiring, cleaning or replacing faulty connectors, updating module software, or replacing the defective module.

Can a software update fix a U1793 code?

In some cases, a software update for the Powertrain Control Module or related systems can resolve communication issues.

Is it safe to drive with a U1793 code?

Driving with this code may lead to reduced hybrid/EV performance or other electrical issues, so it’s best to address the problem promptly to avoid further complications.

Discuss the causes and fixes for U1793 OBDII Code

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