AutoCodes – Chevrolet – B0104 Chevrolet

B0104 Chevrolet Code - Passenger-Side EFS Not Okay Message

Quick Answer

Electronic Frontal Sensor (EFS), also known as a front end sensor, uses a unidirectional 2-wire circuit. Common causes include Faulty Passenger-Side Electronic Frontal Sensor (EFS), Passenger-Side Electronic Frontal Sensor (EFS) harness is open or shorted, Passenger-Side Electronic Frontal Sensor (EFS) 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: B0104 Chevrolet indicates Passenger-Side EFS Not Okay Message.
Common causes: Common causes include Faulty Passenger-Side Electronic Frontal Sensor (EFS), Passenger-Side Electronic Frontal Sensor (EFS) harness is open or shorted, Passenger-Side Electronic Frontal Sensor (EFS) 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 15,088

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 Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0104 Chevrolet Description

Electronic Frontal Sensor (EFS), also known as a front end sensor, uses a unidirectional 2-wire circuit. EFS sensor modulates current on the interface to send identification, State Of Health (SOH) and deployment commands to Sensing and Diagnostic Module (SDM). The SDM serves as a power source and ground for EFS. When ignition is turned on and EFS detects power from SDM, EFS responds by performing internal diagnostics and sending identification to SDM. SDM considers identification message to be valid if received within 5 seconds of EFS powering up. EFS continually communicates a status message to SDM. When fault is detected, SDM will attempt to reset EFS twice by removing and applying power. If fault is still present, SDM will set a Diagnostic Trouble Code (DTC).

OBDII Code B0104 Chevrolet - Passenger-Side EFS Not Okay Message - AutoCodes.com — B0104 Chevrolet Code - Passenger-Side EFS Not Okay Message

What does this mean?

What are the Possible Causes of the DTC B0104 Chevrolet?

Faulty Passenger-Side Electronic Frontal Sensor (EFS)
Passenger-Side Electronic Frontal Sensor (EFS) harness is open or shorted
Passenger-Side Electronic Frontal Sensor (EFS) circuit poor electrical connection
Faulty Sensing and Diagnostic Module (SDM)

How to Fix the DTC B0104 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 B0104 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 B0104 Chevrolet code?

Need more information on how to fix the B0104 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0104 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.

Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

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 B0104 Chevrolet Code

1. What does the OBDII code B0104 for Chevrolet mean?

The B0104 code indicates that there is an issue with the passenger-side EFS (External Front Sensor) system in the vehicle.

2. What are the common symptoms of a B0104 Chevrolet code?

Common symptoms of a B0104 code may include the airbag warning light illuminating on the dashboard, the passenger-side airbag not deploying in an accident, or a "Passenger-Side EFS Not Okay" message on the instrument cluster.

3. What are the possible causes of a B0104 code in a Chevrolet vehicle?

Possible causes of a B0104 code include a faulty passenger-side EFS sensor, damaged wiring or connectors in the airbag system, or a malfunction in the airbag control module.

4. How can I diagnose a B0104 code in my Chevrolet?

Diagnosing a B0104 code typically involves using a diagnostic scanner to retrieve the specific fault code, checking the passenger-side EFS sensor for proper operation, inspecting wiring for damage, and testing the airbag system components for faults.

5. Can I drive my Chevrolet with a B0104 code?

It is not recommended to drive your Chevrolet with a B0104 code present, as it indicates a potential issue with the passenger-side airbag system, which could affect its proper deployment in an accident.

6. How can I repair a B0104 code in my Chevrolet?

Repairing a B0104 code may involve replacing the faulty passenger-side EFS sensor, repairing damaged wiring or connectors, or resetting the airbag control module after fixing the issue.

7. Is it safe to reset the B0104 code in my Chevrolet without fixing the underlying issue?

Resetting the B0104 code without addressing the underlying issue is not recommended, as it may lead to the airbag system not functioning properly in the event of an accident.

8. How much does it cost to repair a B0104 code in a Chevrolet?

The cost of repairing a B0104 code can vary depending on the specific issue causing the code, the labor rates of the repair shop, and the cost of any replacement parts needed.

9. Can a DIY enthusiast fix a B0104 code in a Chevrolet?

While some DIY enthusiasts may be able to diagnose and repair a B0104 code themselves, it is recommended to have the issue addressed by a professional to ensure the airbag system is functioning correctly.

10. How often does a B0104 code occur in Chevrolet vehicles?

The occurrence of a B0104 code in Chevrolet vehicles can vary and is typically influenced by factors such as vehicle age, maintenance history, and driving conditions.