AutoCodes – Cadillac – B3894 Cadillac

B3894 Cadillac 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 Cadillac 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 473

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

What does this mean?

What are the Possible Causes of the DTC B3894 Cadillac?

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 Cadillac?

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 Cadillac 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 B3894 Cadillac Code

1. What does the OBDII code B3894 mean on a Cadillac?

The code B3894 indicates a "Stop Lamp Switch Circuit Plausibility Failure," meaning the vehicle's control module detected an issue with the stop lamp switch signal.

2. What are the symptoms of the B3894 code in a Cadillac?

Common symptoms include malfunctioning brake lights, ABS or traction control warning lights, and possible cruise control failure.

3. What causes the B3894 code to appear?

The code can be triggered by a faulty stop lamp switch, damaged wiring, a malfunctioning brake pedal position sensor, or a misaligned brake pedal assembly.

4. Can I still drive my Cadillac with the B3894 code?

While it may be possible to drive, it's not recommended since the brake lights may not function properly, posing a safety risk.

5. How do I diagnose the B3894 code?

Diagnose the issue by visually inspecting the stop lamp switch, wiring, and connectors, and using a scan tool to monitor the brake pedal position sensor readings.

6. How is the B3894 code fixed on a Cadillac?

Repairs may include replacing the stop lamp switch, repairing damaged wiring or connectors, and recalibrating the brake pedal position sensor if necessary.

7. What tools are needed to fix the B3894 code?

You may need a multimeter to test electrical connections, a scan tool to read live data, and basic hand tools to access and replace components.

8. How much does it cost to repair the B3894 code?

Repair costs can range from $50 to $200, depending on whether the stop lamp switch or wiring needs replacement and if professional labor is required.

9. Can a faulty stop lamp switch cause other issues?

Yes, a faulty stop lamp switch can affect cruise control, ABS, traction control, and even the transmission shift interlock system.

10. How can I prevent the B3894 code from recurring?

Regularly inspect and maintain the brake pedal assembly, wiring, and stop lamp switch to ensure they are functioning properly and free from damage or misalignment.