AutoCodes – GMC – B3894 GMC

B3894 GMC Code - Stop Lamp Switch Circuit Plausibility Failure

Quick Answer

The Body Control Module (BCM) monitors the Stop Lamp Switch Circuit. Common causes include Faulty Stop Lamp Switch Circuit, Stop Lamp Switch Circuit harness is open or shorted, Stop Lamp Switch Circuit 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: B3894 GMC indicates Stop Lamp Switch Circuit Plausibility Failure.
Common causes: Common causes include Faulty Stop Lamp Switch Circuit, Stop Lamp Switch Circuit harness is open or shorted, Stop Lamp Switch Circuit 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 1,047

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3894 GMC Description

The Body Control Module (BCM) monitors the Stop Lamp Switch Circuit. The BCM sets the OBDII code when the Stop Lamp Switch Circuit is not to factory specifications.

OBDII Code B3894 GMC - Stop Lamp Switch Circuit Plausibility Failure - AutoCodes.com — B3894 GMC Code - Stop Lamp Switch Circuit Plausibility Failure

What does this mean?

What are the Possible Causes of the DTC B3894 GMC?

Faulty Stop Lamp Switch Circuit
Stop Lamp Switch Circuit harness is open or shorted
Stop Lamp Switch Circuit circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3894 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3894 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.

Need more information about the B3894 GMC code?

Need more information on how to fix the B3894 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3894 GMC code diagnosed by a professional: Find a repair shop in your area

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 B3894 GMC Code

1. What are the common symptoms of OBDII code B3894 GMC (Stop Lamp Switch Circuit Plausibility Failure)?

- Common symptoms include the brake lights staying on or not working at all, the cruise control not functioning properly, and the vehicle going into limp mode.

2. What are the possible causes of the B3894 GMC code?

- The code can be triggered by a faulty stop lamp switch, a wiring issue in the stop lamp circuit, or a problem with the brake pedal position sensor.

3. How can I diagnose the B3894 GMC code?

- To diagnose the code, you can start by checking the stop lamp switch for proper operation, inspecting the wiring for any damage or loose connections, and testing the brake pedal position sensor.

4. Can I continue driving with the B3894 GMC code?

- It is not recommended to drive with the B3894 code, as it can affect the vehicle's braking system and other safety features. It is best to address the issue promptly.

5. How do I repair the B3894 GMC code?

- The repair process typically involves replacing the faulty stop lamp switch, repairing any damaged wiring, or adjusting the brake pedal position sensor as necessary.

6. Will resetting the code make it go away permanently?

- Resetting the code may turn off the check engine light temporarily, but if the underlying issue is not fixed, the code is likely to reappear after driving the vehicle for some time.

7. Can a DIY enthusiast fix the B3894 GMC code?

- Depending on your mechanical skills and access to tools, some DIY enthusiasts may be able to address the B3894 code by replacing the stop lamp switch or checking the wiring. However, complex issues may require professional assistance.

8. How long does it typically take to resolve the B3894 GMC code?

- The repair time can vary based on the specific cause of the code and the complexity of the repair. Simple fixes like replacing the stop lamp switch can be completed in a relatively short time, while wiring issues may take longer.

9. Will the B3894 GMC code cause a vehicle to fail an emissions test?

- The B3894 code itself may not directly cause a vehicle to fail an emissions test, but it is still important to address the issue as it can affect the proper functioning of the brake lights and other safety features.

10. Are there any preventive measures to avoid the B3894 GMC code in the future?

- Regularly checking and maintaining the stop lamp switch, brake pedal position sensor, and related wiring can help prevent the occurrence of the B3894 code in the future.