AutoCodes – Buick – B2477 Buick

B2477 Buick Code - Reverse Light Relay Shorted To Ground

Quick Answer

When the Platform Zone Module (PZM) receives input that transaxle is in reverse, PZM energizes reverse light relay which will turn on back-up lights. Common causes include Faulty Reverse Light Relay, Reverse Light Relay harness is open or shorted, Reverse Light Relay 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: B2477 Buick indicates Reverse Light Relay Shorted To Ground.
Common causes: Common causes include Faulty Reverse Light Relay, Reverse Light Relay harness is open or shorted, Reverse Light Relay 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 702

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 Dec 09, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2477 Buick Description

When the Platform Zone Module (PZM) receives input that transaxle is in reverse, PZM energizes reverse light relay which will turn on back-up lights. When back-up lights have been commanded on, PZM constantly measures the voltage. The Diagnostic Trouble Code (DTC) B2477 will set when the voltage is approximately equal to the ground. DTC B2477 will clear when the voltage is greater than the ground for at least one monitoring cycle.

OBDII Code B2477 Buick - Reverse Light Relay Shorted To Ground - AutoCodes.com — B2477 Buick Code - Reverse Light Relay Shorted To Ground

What does this mean?

What are the Possible Causes of the DTC B2477 Buick?

Faulty Reverse Light Relay
Reverse Light Relay harness is open or shorted
Reverse Light Relay circuit poor electrical connection
Faulty Platform Zone Module (PZM)

How to Fix the DTC B2477 Buick?

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 B2477 Buick 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 B2477 Buick Code

1. What does OBDII code B2477 mean on a Buick?

Code B2477 indicates that the reverse light relay circuit is shorted to ground, preventing the reverse lights from functioning properly.

2. What are the common symptoms of code B2477 in a Buick?

Common symptoms include reverse lights not working, potential warning lights on the dashboard, and possible failure to meet safety regulations for reverse lighting.

3. What causes the reverse light relay to short to ground?

Causes can include damaged wiring, corroded connectors, water intrusion, or a failed reverse light relay.

4. Can I drive my Buick with code B2477 active?

Yes, you can drive the vehicle, but the reverse lights may not work, which could pose a safety hazard and violate traffic laws.

5. How is code B2477 diagnosed?

A technician will inspect the wiring and connectors in the reverse light circuit, test the relay, and check for signs of a short to ground.

6. How can I fix the B2477 code on my Buick?

Repairs may involve replacing the reverse light relay, repairing damaged wiring, or cleaning corroded connectors.

7. Is replacing the reverse light relay a DIY fix?

If you have basic automotive knowledge and tools, you can replace the relay. However, diagnosing wiring issues may require professional assistance.

8. Will clearing the code B2477 with a scanner fix the issue?

Clearing the code will reset the warning, but the underlying issue causing the short must be repaired to prevent the code from returning.

9. What tools are needed to diagnose and repair code B2477?

Tools may include a multimeter for testing circuits, a code scanner, replacement relays, and basic hand tools for accessing wiring.

10. How much does it cost to fix code B2477 on a Buick?

Repair costs can vary, but replacing a reverse light relay typically costs $20-$50 for parts, while diagnosing and repairing wiring issues could cost $100-$200 or more with labor.