AutoCodes – Chevrolet – B3889 Chevrolet

B3889 Chevrolet Code - Trailer Brake Lamps

Quick Answer

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. Common causes include Faulty Trailer Brake Lamps, Trailer Brake Lamps harness is open or shorted, Trailer Brake Lamps 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: B3889 Chevrolet indicates Trailer Brake Lamps.
Common causes: Common causes include Faulty Trailer Brake Lamps, Trailer Brake Lamps harness is open or shorted, Trailer Brake Lamps 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 660

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 23, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B3889 Chevrolet Description

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The Body Control Module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM applies battery voltage to the center high mounted stop lamp control circuit and Trailer Lighting Control Module. The Trailer Lighting Control Module responds by applying battery voltage to the trailer stop lamp control circuit illuminating the trailer stop lamps.

OBDII Code B3889 Chevrolet - Trailer Brake Lamps - AutoCodes.com — B3889 Chevrolet Code - Trailer Brake Lamps

What does this mean?

What are the Possible Causes of the DTC B3889 Chevrolet?

Faulty Trailer Brake Lamps
Trailer Brake Lamps harness is open or shorted
Trailer Brake Lamps circuit poor electrical connection
Faulty Trailer Lighting Control Module

How to Fix the DTC B3889 Chevrolet?

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 does this mean?

Code Tech Notes

B3889 02 Trailer Brake Lamps Circuit Short to Ground
B3889 04 Trailer Brake Lamps Circuit Open

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3889 Chevrolet 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 B3889 Chevrolet Code

What does the OBDII code B3889 mean for a Chevrolet vehicle?

B3889 indicates an issue with the trailer brake lamps circuit, specifically related to the trailer brake control module or its connection.

What are common symptoms of the B3889 code?

Common symptoms include warning lights on the dashboard, malfunctioning trailer brake lights, or an inoperative trailer brake controller.

What can cause the B3889 code to trigger?

Causes may include a faulty trailer brake control module, damaged wiring or connectors, a blown fuse, or issues with the trailer itself.

How can I diagnose the issue related to code B3889?

Start by checking the trailer brake control module for proper operation, inspect wiring and connectors for damage, and test the fuses associated with the brake lamp circuit.

Can I drive my Chevrolet with the B3889 code?

While it may be safe to drive, the trailer brake functionality may be compromised, which can be dangerous when towing. Itâ€™s recommended to address the issue promptly.

What should I check first if I encounter the B3889 code?

Begin by inspecting the trailer brake control module and its connections, followed by checking for any blown fuses or damaged wiring.

Is it possible to reset the B3889 code without fixing the problem?

Yes, but the code may return once the vehicle's system detects the same issue again, so itâ€™s important to address the underlying problem.

Are there any common repair solutions for the B3889 code?

Common repairs include replacing the trailer brake control module, repairing or replacing damaged wiring or connectors, and replacing blown fuses.

Could a trailer malfunction cause the B3889 code?

Yes, a malfunctioning trailer, such as faulty brake lights or wiring issues, can lead to the B3889 code being triggered in the towing vehicle.

How much does it typically cost to repair the issue related to code B3889?

Repair costs can vary widely depending on the specific issue, but it may range from $100 for simple wiring repairs to several hundred dollars for module replacement.