AutoCodes – GMC – B3951 GMC

B3951 GMC Code - Right Rear Turn Signal Circuit

Quick Answer

Ground is applied at all times to the turn signal/multifunction switch. Common causes include Faulty Right Rear Turn Signal Lamp, Right Rear Turn Signal Lamp harness is open or shorted, Right Rear Turn Signal Lamp 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: B3951 GMC indicates Right Rear Turn Signal Circuit.
Common causes: Common causes include Faulty Right Rear Turn Signal Lamp, Right Rear Turn Signal Lamp harness is open or shorted, Right Rear Turn Signal Lamp 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 1,068

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Basic DIY (1 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 17, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B3951 GMC Description

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START positions. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the Body Control Module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument cluster requesting the respective turn signal indicator be pulsed ON and OFF. The Diagnostic Trouble Code (DTC) will be set when the BCM detects a short to voltage, short to ground, or an open/high resistance in the right rear turn signal control circuit.

OBDII Code B3951 GMC - Right Rear Turn Signal Circuit - AutoCodes.com — B3951 GMC Code - Right Rear Turn Signal Circuit

What does this mean?

What are the Possible Causes of the DTC B3951 GMC?

Faulty Right Rear Turn Signal Lamp
Right Rear Turn Signal Lamp harness is open or shorted
Right Rear Turn Signal Lamp circuit poor electrical connection

How to Fix the DTC B3951 GMC?

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

B3951:01 Right Rear Turn Signal Circuit Short to Battery
B3951:02 Right Rear Turn Signal Circuit Short to Ground
B3951:04 Right Rear Turn Signal Circuit Open

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3951 GMC 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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Information for Specific GMC Models

B3951 2014 GMC Sierra — Right Rear Turn Signal Circuit
B3951 2015 GMC Sierra — Right Rear Turn Signal Circuit
B3951 2016 GMC Sierra — Right Rear Turn Signal Circuit
B3951 2017 GMC Sierra — Right Rear Turn Signal Circuit
B3951 2018 GMC Sierra — Right Rear Turn Signal Circuit

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 B3951 GMC Code

1. What are the common symptoms of OBDII code B3951 GMC related to the Right Rear Turn Signal Circuit?

- The common symptoms include a malfunctioning or completely non-functional right rear turn signal light on the vehicle.

2. What are the potential causes of OBDII code B3951 GMC for the Right Rear Turn Signal Circuit?

- Possible causes can include a faulty right rear turn signal bulb, a damaged wiring harness, a defective turn signal socket, or a problem with the vehicle's body control module.

3. How can I diagnose the issue causing OBDII code B3951 GMC for the Right Rear Turn Signal Circuit?

- You can start by visually inspecting the right rear turn signal bulb, checking the wiring for any visible damage, testing the turn signal socket for proper connectivity, and using a diagnostic scan tool to read the fault codes stored in the vehicle's system.

4. Are there any quick repair tips for fixing OBDII code B3951 GMC related to the Right Rear Turn Signal Circuit?

- Quick repair tips may include replacing the right rear turn signal bulb, repairing any damaged wiring, ensuring a secure connection at the turn signal socket, or resetting the vehicle's body control module.

5. Can OBDII code B3951 GMC cause any safety concerns with the right rear turn signal?

- Yes, a malfunctioning right rear turn signal can compromise the visibility of your vehicle to other drivers, potentially leading to hazardous situations on the road. It is essential to address this issue promptly.

6. Is it possible to reset OBDII code B3951 GMC for the Right Rear Turn Signal Circuit without repairs?

- Resetting the code without addressing the underlying issue may temporarily clear the fault code, but the problem will likely reoccur until the root cause is fixed. It is recommended to diagnose and fix the issue to prevent further issues.

7. How do I know if the OBDII code B3951 GMC for the Right Rear Turn Signal Circuit has been successfully resolved?

- After making the necessary repairs, you can use a diagnostic scan tool to clear the fault codes from the vehicle's system. Then, test the right rear turn signal to ensure it functions correctly without triggering the code again.

8. Can extreme weather conditions affect the right rear turn signal circuit and trigger OBDII code B3951 GMC?

- Yes, extreme weather conditions like heavy rain, snow, or extreme temperatures can potentially damage the wiring or components in the right rear turn signal circuit, leading to the triggering of OBDII code B3951 GMC.

9. Are there any recalls or service bulletins related to OBDII code B3951 GMC for the Right Rear Turn Signal Circuit?

- It's advisable to check with the manufacturer or authorized service centers for any recalls or service bulletins related to this specific OBDII code to see if there are known issues or remedies available.

10. Can a DIY enthusiast with basic automotive knowledge fix OBDII code B3951 GMC for the Right Rear Turn Signal Circuit?

- Depending on the specific cause of the issue, a DIY enthusiast with basic automotive knowledge may be able to address simple fixes like bulb replacement or checking connections. However, more complex issues may require professional diagnosis and repair.