AutoCodes – Generic – B3884

B3884 Code - Center High Mounted Stop Lamp Circuit

Quick Answer

The brake pedal position sensor is used to sense the action of the driver's application of the brake pedal. Common causes include Faulty Center High Mounted Stop Lamp, Center High Mounted Stop Lamp harness is open or shorted, Center High Mounted Stop 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: B3884 indicates Center High Mounted Stop Lamp Circuit.
Common causes: Common causes include Faulty Center High Mounted Stop Lamp, Center High Mounted Stop Lamp harness is open or shorted, Center High Mounted Stop 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 2,203

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 Jun 16, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B3884 Description

The brake pedal position sensor is used to sense the action of the driver's application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The Body Control Module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM energizes the stop lamp relay by applying a voltage to the stop lamp relay control circuit. When the stop lamp relay is energized, the relay switch contacts close, and battery voltage is applied to the Center High Mounted Stop Lamp (CHMSL) control circuit which illuminates the CHMSL. The Diagnostic Trouble Code (DTC) will be set when the BCM detects a malfunction in the stop lamp relay control circuit.

OBDII Code B3884 - Center High Mounted Stop Lamp Circuit - AutoCodes.com — B3884 Code - Center High Mounted Stop Lamp Circuit

What does this mean?

What are the Possible Causes of the DTC B3884?

Faulty Center High Mounted Stop Lamp
Center High Mounted Stop Lamp harness is open or shorted
Center High Mounted Stop Lamp circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3884?

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

B3884:01 Center High Mounted Stop Lamp Circuit Short to Battery
B3884:02 Center High Mounted Stop Lamp Circuit Short to Ground
B3884:04 Center High Mounted Stop Lamp Circuit Open

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3884 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 B3884 code?

Need more information on how to fix the B3884 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3884 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B3884 Buick — Center High Mounted Stop Lamp Circuit
B3884 Cadillac — Center High Mounted Stop Lamp Circuit
B3884 Chevrolet — Center High Mounted Stop Lamp Circuit
B3884 GMC — Center High Mounted Stop Lamp 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 B3884 Code

1. What does OBDII code B3884 mean?

Code B3884 indicates an issue with the Center High Mounted Stop Lamp (CHMSL) circuit, which may involve a malfunction in the wiring, bulb, or control module related to the third brake light.

2. What are the symptoms of code B3884?

Common symptoms include the center high-mounted stop lamp not illuminating when the brakes are applied or intermittent operation of the lamp.

3. What causes the B3884 code to appear?

The code can be caused by a burnt-out bulb, damaged wiring, corroded connectors, a faulty brake light switch, or a malfunctioning control module.

4. How do I diagnose the B3884 code?

Start by inspecting the center brake light bulb for damage, checking the wiring and connectors for signs of corrosion or breaks, and testing the brake light switch for proper operation.

5. Can I still drive with a B3884 code?

Yes, you can drive with this code, but itâ€™s not recommended as the center brake light is a safety feature, and its malfunction could increase the risk of accidents.

6. How is the B3884 code repaired?

Repairs may involve replacing the center brake light bulb, repairing or replacing damaged wiring, cleaning corroded connectors, or replacing the brake light switch or control module.

7. How much does it cost to fix a B3884 code?

The repair cost varies depending on the root cause. Replacing a bulb may cost $10-$50, while wiring or module repairs may cost $100-$500 or more.

8. Can a blown fuse cause the B3884 code?

Yes, a blown fuse related to the CHMSL circuit can cause this code. Check the vehicleâ€™s fuse box and replace any blown fuses.

9. Will clearing the code fix the problem?

Clearing the code without addressing the underlying issue will not fix the problem. The code will likely return until the cause is resolved.

10. Is the B3884 code specific to any vehicle make or model?

No, the B3884 code is a generic OBDII code and can appear on various vehicle makes and models with a center high-mounted stop lamp. However, troubleshooting steps may differ slightly depending on the vehicle.