AutoCodes – Generic – B3951

B3951 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 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 3,815

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

What does this mean?

What are the Possible Causes of the DTC B3951?

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?

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 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 Makes

B3951 Buick — Right Rear Turn Signal Circuit
B3951 Cadillac — Right Rear Turn Signal Circuit
B3951 Chevrolet — Right Rear Turn Signal Circuit
B3951 GMC — Right Rear Turn Signal Circuit
B3951 Pontiac — Right Rear Turn Signal Circuit
B3951 Saturn — 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 Code

1. What are the common symptoms of OBDII code B3951 (Right Rear Turn Signal Circuit)?

- The common symptoms include the right rear turn signal not functioning properly or not working at all.

2. What are possible causes of OBDII code B3951?

- Possible causes include a faulty right rear turn signal bulb, a damaged wiring harness, a defective turn signal switch, or a malfunctioning body control module.

3. How can I diagnose the issue related to OBDII code B3951?

- You can start by visually inspecting the right rear turn signal bulb and wiring for any damage. Using a multimeter, you can also test for continuity in the circuit and check for any loose connections.

4. What are some repair tips for fixing OBDII code B3951?

- Check and replace the right rear turn signal bulb if it is burnt out. Inspect and repair any damaged wiring. If no issues are found, consider testing and potentially replacing the turn signal switch or the body control module.

5. Can I drive my vehicle with OBDII code B3951 (Right Rear Turn Signal Circuit) active?

- It is generally safe to drive with this code, but it is important to address the issue promptly to ensure proper turn signal function for safety reasons.

6. Is resetting the OBDII code B3951 enough to fix the right rear turn signal issue?

- Resetting the code may temporarily turn off the warning light, but it will not fix the underlying issue causing the code. Proper diagnosis and repair are necessary.

7. How much does it typically cost to repair OBDII code B3951?

- The cost of repair can vary depending on the root cause of the issue. Replacing a bulb may be relatively inexpensive, while fixing a wiring harness or replacing a module can be more costly.

8. Are there any preventive measures to avoid OBDII code B3951 in the future?

- Regularly checking and replacing turn signal bulbs at the first sign of dimness can help prevent issues. Keeping an eye out for any unusual behavior in the turn signals can also help catch problems early.

9. Can extreme weather conditions affect the triggering of OBDII code B3951?

- Yes, extreme weather conditions can potentially affect the electrical components involved in the right rear turn signal circuit, leading to issues that trigger the code.

10. Will fixing OBDII code B3951 require specialized tools or equipment?

- Basic tools like a multimeter, screwdrivers, and replacement bulbs are typically sufficient for diagnosing and repairing issues related to OBDII code B3951.