AutoCodes – Chevrolet – B256B Chevrolet

B256B Chevrolet Code - Cargo Lamps Switch Circuit Malfunction

Quick Answer

The cargo lamp relay is always supplied with battery voltage. Common causes include Faulty Cargo Lamps Switch, Cargo Lamps Switch harness is open or shorted, Cargo Lamps Switch 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: B256B Chevrolet indicates Cargo Lamps Switch Circuit Malfunction.
Common causes: Common causes include Faulty Cargo Lamps Switch, Cargo Lamps Switch harness is open or shorted, Cargo Lamps Switch 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 470

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on May 26, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B256B Chevrolet Description

The cargo lamp relay is always supplied with battery voltage. The cargo lamp switch signal circuit is grounded momentarily by pressing the cargo lamp switch. The Body Control Module (BCM) energizes the cargo lamp relay by applying ground to the cargo lamp relay control circuit. When the cargo lamp relay is energized, the relay switch contacts close, and battery voltage is applied through the F9DR fuse to the cargo lamp control circuit which illuminates the cargo lamps. The Diagnostic Trouble Code (DTC) will be set when the BCM detects a short to ground in the cargo lamp switch signal circuit.

OBDII Code B256B Chevrolet - Cargo Lamps Switch Circuit Malfunction - AutoCodes.com — B256B Chevrolet Code - Cargo Lamps Switch Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC B256B Chevrolet?

Faulty Cargo Lamps Switch
Cargo Lamps Switch harness is open or shorted
Cargo Lamps Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B256B Chevrolet?

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 B256B Chevrolet 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 B256B Chevrolet code?

Need more information on how to fix the B256B Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B256B Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

B256B 2014 Chevrolet Silverado — Cargo Lamps Switch Circuit Malfunction
B256B 2015 Chevrolet Silverado — Cargo Lamps Switch Circuit Malfunction
B256B 2016 Chevrolet Silverado — Cargo Lamps Switch Circuit Malfunction
B256B 2017 Chevrolet Silverado — Cargo Lamps Switch Circuit Malfunction
B256B 2018 Chevrolet Silverado — Cargo Lamps Switch Circuit Malfunction

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 B256B Chevrolet Code

1. What does the OBDII code B256B mean on a Chevrolet?

The B256B code indicates a malfunction in the cargo lamps switch circuit, which controls the operation of the vehicle's cargo lights.

2. What are common symptoms of the B256B code?

Symptoms include non-functional or flickering cargo lamps, a dashboard warning light, or the inability to turn the cargo lamps on or off.

3. What causes the B256B code to appear in a Chevrolet?

Common causes include a faulty cargo lamp switch, damaged wiring or connectors in the cargo lamp circuit, or a problem with the body control module (BCM).

4. Can I still drive my Chevrolet with the B256B code?

Yes, you can usually drive the vehicle, but the cargo lamp functionality may be impaired, which can be inconvenient for loading or unloading in low-light conditions.

5. How do I diagnose the B256B code in my Chevrolet?

Start by inspecting the cargo lamp switch, wiring, and connectors for damage or corrosion. Use a diagnostic scanner to confirm the code and test the circuit's continuity.

6. How do I fix the B256B code on my Chevrolet?

Repairs may include replacing the cargo lamp switch, repairing or replacing damaged wiring, or reprogramming or replacing the body control module if necessary.

7. How much does it cost to fix the B256B code?

The cost depends on the root cause. Replacing the cargo lamp switch may cost $50â€“$150, while wiring repairs or BCM replacement can be more expensive.

8. Can a blown fuse cause the B256B code?

Yes, a blown fuse in the cargo lamp circuit can cause this code. Check and replace the fuse if necessary.

9. Will clearing the code fix the issue permanently?

Clearing the code without addressing the underlying issue will only provide a temporary fix, as the code will likely reappear.

10. Can I fix the B256B code myself?

If you have basic automotive knowledge, you can inspect the switch, wiring, and fuse yourself. However, complex issues like BCM failure may require professional assistance.