AutoCodes – GMC – B0104 GMC

B0104 GMC 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 GMC 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 5,019

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 Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0104 GMC 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 GMC - Passenger-Side EFS Not Okay Message - AutoCodes.com — B0104 GMC Code - Passenger-Side EFS Not Okay Message

What does this mean?

What are the Possible Causes of the DTC B0104 GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

Get the B0104 GMC 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 GMC Code

1. What are the common symptoms of OBDII code B0104 GMC (Passenger-Side EFS Not Okay Message)?

- The common symptoms include the airbag warning light illuminating on the dashboard and a message indicating "Passenger-Side EFS Not Okay."

2. What are some possible causes of OBDII code B0104 GMC?

- The code B0104 GMC typically indicates a fault with the passenger-side electronic front sensor (EFS). Possible causes include a malfunctioning sensor, wiring issues, or a faulty airbag control module.

3. How serious is the OBDII code B0104 GMC?

- The B0104 code is related to the passenger-side airbag system, so it is considered a serious issue that should be addressed promptly to ensure the proper functioning of the airbag in case of an accident.

4. Can I continue driving with the OBDII code B0104 GMC present?

- It is not recommended to continue driving with the B0104 code present, as it indicates a potential problem with the passenger-side airbag system, which could affect its functionality in the event of a collision.

5. How can I diagnose and repair OBDII code B0104 GMC?

- Diagnosing and repairing the B0104 code typically involves using a scan tool to identify the specific issue with the passenger-side EFS, checking the wiring and connections for any faults, and replacing any faulty components as needed.

6. Can I reset the OBDII code B0104 GMC without fixing the underlying issue?

- While you can clear the code temporarily by resetting the vehicle's computer, it is important to address the underlying problem causing the B0104 code to prevent it from reoccurring and ensure the proper operation of the airbag system.

7. Are there any DIY tips for fixing the OBDII code B0104 GMC?

- DIY tips for fixing the B0104 code may include checking the sensor connections for corrosion or damage, inspecting the wiring for any breaks or shorts, and ensuring all connections are secure before considering sensor or module replacement.

8. How much does it typically cost to repair OBDII code B0104 GMC at a dealership or repair shop?

- The cost of repairing the B0104 code can vary depending on the specific issue causing the fault. Repair costs may include diagnostic fees, parts replacement, and labor costs, which can range from a few hundred to over a thousand dollars.

9. Is OBDII code B0104 GMC covered under any vehicle warranties?

- Depending on the vehicle's warranty coverage, the repair for the B0104 code may be covered if it falls within the terms of the warranty. It is advisable to check with the vehicle manufacturer or dealership to determine warranty coverage for this issue.

10. How can I prevent OBDII code B0104 GMC from occurring in the future?

- To prevent the B0104 code from occurring in the future, regular maintenance and inspection of the airbag system, including the sensors and wiring, can help identify and address any potential issues before they trigger the code.