AutoCodes – Buick – B3120 Buick

B3120 Buick Code - Keyless Entry Antenna 2

Quick Answer

The passenger front door handle antenna is located in the passenger front door handle assembly and is used to establish low frequency communications with the keyless entry transmitter. Common causes include Faulty Passenger Exterior Door Handle Assembly, Passenger Exterior Door Handle Assembly harness is open or shorted, Passenger Exterior Door Handle Assembly 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: B3120 Buick indicates Keyless Entry Antenna 2.
Common causes: Common causes include Faulty Passenger Exterior Door Handle Assembly, Passenger Exterior Door Handle Assembly harness is open or shorted, Passenger Exterior Door Handle Assembly 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 1,241

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 Mar 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

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

Code B3120 Buick Description

The passenger front door handle antenna is located in the passenger front door handle assembly and is used to establish low frequency communications with the keyless entry transmitter. As a vehicle with locked doors is approached with a keyless entry transmitter and the exterior door handle button is pressed, the Keyless Entry Control Module communicates with the passenger front door handle keyless entry antenna. The Diagnostic Trouble Code (DTC) sets when the keyless entry control module detects a short to ground on the passenger front door keyless entry antenna signal circuit.

OBDII Code B3120 Buick - Keyless Entry Antenna 2 - AutoCodes.com — B3120 Buick Code - Keyless Entry Antenna 2

What does this mean?

What are the Possible Causes of the DTC B3120 Buick?

Faulty Passenger Exterior Door Handle Assembly
Passenger Exterior Door Handle Assembly harness is open or shorted
Passenger Exterior Door Handle Assembly circuit poor electrical connection
Faulty Keyless Entry Control Module

How to Fix the DTC B3120 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 B3120 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.

Need more information about the B3120 Buick code?

Need more information on how to fix the B3120 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3120 Buick 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 B3120 Buick Code

1. What does the OBDII code B3120 mean on a Buick?

The B3120 code indicates an issue with the Keyless Entry Antenna 2, which is responsible for receiving signals from the key fob for remote locking, unlocking, or starting.

2. What are the symptoms of the B3120 code in a Buick?

Common symptoms include intermittent or non-functional keyless entry, difficulty unlocking or locking doors remotely, and failure of the remote start feature.

3. What causes the B3120 Keyless Entry Antenna 2 code to appear?

Possible causes include a damaged or faulty keyless entry antenna, wiring issues such as frayed or disconnected wires, or interference from other electronic devices.

4. How is the B3120 code diagnosed?

A technician will use a scan tool to verify the code, inspect the antenna and its wiring for damage or disconnections, and test the antenna's signal strength and functionality.

5. Can I still use my Buick if the B3120 code is active?

Yes, the vehicle can still be driven, but the keyless entry and remote start features may not work properly until the issue is resolved.

6. How do I fix the B3120 Keyless Entry Antenna 2 issue?

Repairs may involve replacing the faulty keyless entry antenna, repairing or reconnecting damaged wiring, or reprogramming the antenna if necessary.

7. How much does it cost to repair the B3120 code on a Buick?

Repair costs vary depending on the extent of the issue, but replacing a keyless entry antenna typically costs between $100 and $300, including parts and labor.

8. Can a weak key fob battery cause the B3120 code?

No, a weak key fob battery won't trigger this code, but it may cause similar symptoms. Replacing the battery is a good first step to rule out key fob issues.

9. Will clearing the B3120 code fix the problem?

Clearing the code without addressing the underlying issue will only temporarily remove it, and the problem will likely return.

10. Is the B3120 code a common issue for Buick vehicles?

While not extremely common, the B3120 code can occur in Buicks, especially if there is physical damage to the antenna or its wiring, or if the vehicle is exposed to strong electronic interference.