Engine-CodesGMC – B3887 GMC

B3887 GMC Code - Trailer Left Turn Signal Circuit

Quick Answer

The B3887 GMC code indicates a fault in the trailer left turn signal circuit of the vehicle. Common causes include Damaged or broken wiring in the trailer left turn signal circuit, Corroded or loose connectors in the circuit, Faulty bulbs in the trailer left turn signal. 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
B3887 GMC indicates Trailer Left Turn Signal Circuit.
Common causes
Common causes include Damaged or broken wiring in the trailer left turn signal circuit, Corroded or loose connectors in the circuit, Faulty bulbs in the trailer left turn signal.
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 16, 2024
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Code B3887 GMC Description

The B3887 GMC code indicates a fault in the trailer left turn signal circuit of the vehicle. This code is typically triggered when the control module detects an issue with the electrical circuit responsible for the left turn signal on a trailer connected to the vehicle. The turn signal circuit is crucial for indicating the driver's intention to turn left, ensuring safety on the road.

OBDII Code B3887 GMC - Trailer Left Turn Signal Circuit
B3887 GMC Code - Trailer Left Turn Signal Circuit

Common Causes of B3887 GMC

  1. Damaged or broken wiring in the trailer left turn signal circuit
  2. Corroded or loose connectors in the circuit
  3. Faulty bulbs in the trailer left turn signal
  4. Malfunctioning control module for the trailer turn signal
  5. Water damage or exposure causing electrical issues

Symptoms of B3887 GMC

  1. Trailer left turn signal not working
  2. Rapid flashing of the trailer left turn signal
  3. Dim or flickering trailer left turn signal
  4. Dashboard indicator for trailer turn signal malfunction
  5. Trailer left turn signal staying on continuously

How to Fix B3887 GMC

  1. Inspect the trailer left turn signal circuit for any visible damage or corrosion.
  2. Test the bulbs in the trailer left turn signal for continuity and replace any faulty bulbs.
  3. Check and clean the connectors in the circuit to ensure a secure connection.
  4. Scan the vehicle's control module for error codes and reset if necessary.
  5. Test the trailer left turn signal after repairs to ensure proper functionality.

Cost to Fix B3887 GMC

The typical repair costs for addressing the B3887 GMC code related to the trailer left turn signal circuit can vary depending on the extent of the issue and the specific components that require replacement. On average, the repair costs for this issue can range from $100 to $300, including parts and labor. It's important to note that diagnosis time and labor rates at auto repair shops can vary based on location, vehicle make and model, and engine type. It is advisable to check with local auto repair shops for a more accurate estimate.

Tech Notes for B3887 GMC

B3887 02 Trailer Left Turn Signal Circuit Short to Ground

B3887 04 Trailer Left Turn Signal Circuit Open

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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 B3887 GMC Code

What does the OBDII code B3887 indicate for a GMC vehicle?

The B3887 code indicates a malfunction in the trailer left turn signal circuit, often related to issues with the trailer wiring or the vehicle’s tow package.

What are the common symptoms associated with the B3887 code?

Common symptoms include a malfunctioning left turn signal on the trailer, warning lights on the dashboard, or a message indicating a trailer fault.

What are potential causes of the B3887 code?

Potential causes include damaged wiring in the trailer harness, a faulty trailer connector, a blown fuse, or problems with the vehicle’s body control module.

How can I diagnose the B3887 code effectively?

To diagnose, check the trailer connector for corrosion or damage, inspect the wiring harness for breaks, and test the left turn signal circuit for continuity.

What should I do if my trailer’s left turn signal isn’t working?

First, check the trailer's bulb and wiring. If they are fine, inspect the vehicle's trailer connector and wiring for issues, and consider testing the vehicle’s turn signal system.

Are there any common fixes for the B3887 code?

Common fixes include repairing or replacing damaged wiring, cleaning or replacing the trailer connector, and ensuring all connections are secure and corrosion-free.

Can I drive my GMC if the B3887 code is active?

While you can drive the vehicle, it’s advisable to fix the issue to ensure safe towing and compliance with traffic regulations regarding trailers.

Will clearing the B3887 code fix the issue permanently?

Clearing the code may reset the warning temporarily, but if the underlying issue isn’t resolved, the code will likely reappear.

Is it safe to tow a trailer with a B3887 code present?

Towing with this code active may not be safe, as the left turn signal on the trailer may not function properly, increasing the risk of accidents.

Can a malfunctioning body control module cause the B3887 code?

Yes, a faulty body control module can affect the trailer signal circuits, leading to the B3887 code being triggered if it fails to communicate correctly.

Discuss the causes and fixes for B3887 GMC OBDII Code

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