AutoCodes – Buick – B2577 Buick

B2577 Buick Code - ALC Relay Control Circuit Is Open/Shorted To Ground

Quick Answer

The Body Control Module (BCM) turns on the Automatic Lighting Control (ALC) Relay when the ambient light sensor senses a dark condition. Common causes include Faulty Automatic Lighting Control (ALC) Relay, Automatic Lighting Control (ALC) Relay harness is open or shorted, Automatic Lighting Control (ALC) 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: B2577 Buick indicates ALC Relay Control Circuit Is Open/Shorted To Ground.
Common causes: Common causes include Faulty Automatic Lighting Control (ALC) Relay, Automatic Lighting Control (ALC) Relay harness is open or shorted, Automatic Lighting Control (ALC) 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 918

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 Jan 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code B2577 Buick Description

The Body Control Module (BCM) turns on the Automatic Lighting Control (ALC) Relay when the ambient light sensor senses a dark condition. Battery positive voltage is supplied to the ALC relay at all times through the LH HDLP fuse. The BCM grounds the ALC relay control circuit in order to activate the relay.

OBDII Code B2577 Buick - ALC Relay Control Circuit Is Open/Shorted To Ground - AutoCodes.com — B2577 Buick Code - ALC Relay Control Circuit Is Open/Shorted To Ground

What does this mean?

What are the Possible Causes of the DTC B2577 Buick?

Faulty Automatic Lighting Control (ALC) Relay
Automatic Lighting Control (ALC) Relay harness is open or shorted
Automatic Lighting Control (ALC) Relay circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B2577 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 B2577 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.