AutoCodes – Generic – B3884:04

B3884:04 Code - Center High Mounted Stop Lamp Circuit Open

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: B3884:04 indicates Center High Mounted Stop Lamp Circuit Open.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 442

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code B3884:04 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 an open/high resistance in the stop lamp relay control circuit.

OBDII Code B3884:04 - Center High Mounted Stop Lamp Circuit Open - AutoCodes.com — B3884:04 Code - Center High Mounted Stop Lamp Circuit Open

What does this mean?

What are the Possible Causes of the DTC B3884:04?

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 B3884:04?

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 B3884:04 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 B3884:04 code?

Need more information on how to fix the B3884:04 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3884:04 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 B3884:04 Code

1. What does the OBDII code B3884:04 mean?

The code B3884:04 indicates an open circuit in the Center High Mounted Stop Lamp (CHMSL) circuit, which prevents the lamp from functioning properly.

2. What are the symptoms of the B3884:04 code?

The primary symptom is that the center high-mounted stop lamp (third brake light) does not illuminate when the brakes are applied.

3. What causes the B3884:04 code to appear?

Common causes include a burned-out CHMSL bulb, damaged or corroded wiring, a faulty lamp assembly, or a defective brake light switch.

4. Is the B3884:04 code serious?

While it may not affect vehicle performance, it is a safety concern since the third brake light is crucial for alerting drivers behind you when you’re braking.

5. How do I diagnose the B3884:04 code?

Start by checking the CHMSL bulb for damage or burnout, inspect the wiring and connectors for corrosion or breaks, and test the brake light switch for proper operation.

6. Can I drive with the B3884:04 code active?

Yes, but it’s not recommended as the third brake light is required by law in many regions and is essential for road safety.

7. How can I fix the B3884:04 code?

Depending on the cause, you may need to replace the CHMSL bulb, repair or replace damaged wiring, clean corroded connectors, or replace the brake light switch.

8. How much does it cost to repair the B3884:04 code?

Repair costs can range from $10 to $50 for a new bulb to $100 or more if wiring repairs or component replacements are necessary.

9. Can a blown fuse cause the B3884:04 code?

Yes, a blown fuse in the brake light circuit can interrupt power to the CHMSL, triggering this code.

10. Will clearing the code fix the B3884:04 issue?

No, clearing the code will not resolve the underlying problem. The issue in the CHMSL circuit must be diagnosed and repaired to prevent the code from returning.