AutoCodes – Generic – C2806

C2806 Code - Trailer Brake Output Circuit Short To VBattery

Quick Answer

The braking energy that is provided to the trailer is varied with a Pulse Width Modulated (PWM) signal along the circuit that switches between 0 volt and battery voltage, the higher the duty cycle the more braking power available. Common causes include Faulty Trailer Brake Control (TBC) Module, Trailer Brake Control (TBC) Module harness is open or shorted, Trailer Brake Control (TBC) 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
C2806 indicates Trailer Brake Output Circuit Short To VBattery .
Common causes
Common causes include Faulty Trailer Brake Control (TBC) Module, Trailer Brake Control (TBC) Module harness is open or shorted, Trailer Brake Control (TBC) 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 2,585
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jun 14, 2020
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Code C2806 Description

The braking energy that is provided to the trailer is varied with a Pulse Width Modulated (PWM) signal along the circuit that switches between 0 volt and battery voltage, the higher the duty cycle the more braking power available. The Trailer Brake Control (TBC) Module varies the PWM signal based on various inputs such as the brake pressure transducer, TBC module manual slider switch and the TBC module gain buttons. With the vehicle stationary and with the manual slider switch fully to the left with a gain of 10, there should be greater than 10-12 volts supplied to pin 3 of the 7-pin trailer tow connector. Every 4 seconds the TBC module sends a voltage pulse along circuit CAT19 (BU) to pin 3 of the 7-pin trailer tow connector to determine whether or not a trailer is connected.
OBDII Code C2806 - Trailer Brake Output Circuit Short To VBattery  - AutoCodes.com
C2806 Code - Trailer Brake Output Circuit Short To VBattery

What are the Possible Causes of the DTC C2806?

  • Faulty Trailer Brake Control (TBC) Module
  • Trailer Brake Control (TBC) Module harness is open or shorted
  • Trailer Brake Control (TBC) Module circuit poor electrical connection

How to Fix the DTC C2806?

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 C2806 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.

Need more information about the C2806 code?

Need more information on how to fix the C2806 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C2806 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

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 C2806 Code

1. What are common symptoms of OBDII code C2806 (Trailer Brake Output Circuit Short To VBattery)?

The common symptoms of this code include the trailer brake system not functioning properly, warning lights illuminated on the dashboard, and potential issues with trailer brake lights.

2. What are the possible causes of OBDII code C2806?

Possible causes of this code include a short circuit in the trailer brake output circuit, damaged wiring or connectors related to the trailer brake system, or a malfunctioning trailer brake module.

3. How can I diagnose the Trailer Brake Output Circuit Short To VBattery issue?

Diagnosing this issue involves inspecting the trailer brake wiring, connectors, and module for any visible damage or signs of a short circuit. Using a multimeter to test the continuity and voltage in the circuit can help pinpoint the exact problem.

4. Can a DIY enthusiast repair OBDII code C2806?

If you have experience with automotive electrical systems and the necessary tools, you may be able to repair this code yourself by identifying and fixing the short circuit in the trailer brake output circuit. However, if you are unsure, it is recommended to seek professional help.

5. Is it safe to drive with OBDII code C2806 active?

It is not recommended to drive with this code active, as it indicates a problem with the trailer brake system that could affect your ability to brake safely, especially when towing a trailer.

6. What are the potential risks of ignoring OBDII code C2806?

Ignoring this code can lead to further damage to the trailer brake system, potential safety hazards while towing, and possible failures during brake application.

7. How much does it typically cost to repair OBDII code C2806?

The cost of repairing this code can vary depending on the extent of the damage and the parts needed for repair. It is advisable to obtain quotes from different mechanics or repair shops for an accurate estimate.

8. Can extreme weather conditions cause OBDII code C2806 to trigger?

Extreme weather conditions, such as exposure to moisture or extreme temperatures, can potentially lead to damage in the trailer brake wiring and components, which may trigger this fault code.

9. How can I prevent OBDII code C2806 from recurring in the future?

To prevent this code from recurring, regularly inspect and maintain the trailer brake system, ensure proper installation of trailer brake components, and protect wiring from damage due to environmental factors.

10. Is OBDII code C2806 a common issue in specific vehicle models?

While this fault code can occur in various vehicles equipped with a trailer brake system, it may be more common in trucks or SUVs designed for towing due to the increased usage of the trailer brake system.

Discuss the causes and fixes for C2806 OBDII Code

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