AutoCodes – GMC – B0101 GMC

B0101 GMC Code - Driver-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 Driver-Side Electronic Frontal Sensor (EFS), Driver-Side Electronic Frontal Sensor (EFS) harness is open or shorted, Driver-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: B0101 GMC indicates Driver-Side EFS Not Okay Message.
Common causes: Common causes include Faulty Driver-Side Electronic Frontal Sensor (EFS), Driver-Side Electronic Frontal Sensor (EFS) harness is open or shorted, Driver-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 4,635

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 B0101 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 B0101 GMC - Driver-Side EFS Not Okay Message - AutoCodes.com — B0101 GMC Code - Driver-Side EFS Not Okay Message

What does this mean?

What are the Possible Causes of the DTC B0101 GMC?

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

How to Fix the DTC B0101 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 B0101 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 B0101 GMC code?

Need more information on how to fix the B0101 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0101 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 B0101 GMC Code

1. What are the common symptoms of OBDII code B0101 GMC (Driver-Side EFS Not Okay Message)?

- Common symptoms include the airbag warning light illuminated on the dashboard, potential loss of functionality of the driver-side airbag, and the display of a "Driver-Side EFS Not Okay" message.

2. What can cause the OBDII code B0101 GMC to appear?

- The code B0101 usually indicates an issue with the Electronic Front Sensor (EFS) located on the driver-side of the vehicle. Possible causes include a faulty EFS, damaged wiring harness, or a malfunction in the airbag control module.

3. How can I diagnose the root cause of the OBDII code B0101 GMC?

- To diagnose the issue, it is recommended to use a diagnostic scanner to retrieve the specific fault codes. Additionally, a thorough visual inspection of the EFS, wiring, and connectors can help identify any visible damage or issues.

4. What are some repair tips for fixing the Driver-Side EFS Not Okay Message?

- Repair tips may include checking and repairing any damaged wiring or connectors, replacing the faulty EFS sensor, and ensuring proper connections and grounding. It is advisable to follow the manufacturer's repair procedures outlined in the vehicle's service manual.

5. Can I drive my vehicle with the OBDII code B0101 GMC present?

- It is not recommended to drive the vehicle with the B0101 code active, especially if it pertains to the driver-side airbag system. Addressing the issue promptly is crucial to ensure the proper functioning of the safety systems.

6. How serious is the OBDII code B0101 GMC?

- The B0101 code related to the driver-side EFS not okay message is a serious issue as it directly affects the functionality of the driver-side airbag system, compromising the safety of the vehicle occupants in the event of a collision.

7. Can I reset the OBDII code B0101 GMC on my own?

- While you can clear the code with a diagnostic scanner, it is essential to address the underlying problem causing the code to prevent it from reoccurring. Simply clearing the code without fixing the issue may lead to potential safety risks.

8. How much does it cost to repair the OBDII code B0101 GMC?

- Repair costs for the B0101 code can vary depending on the root cause of the issue, the extent of the damage, and the labor rates in your area. It is advisable to consult with a certified mechanic or dealership for an accurate estimate.

9. Are there any recalls or service bulletins related to the OBDII code B0101 GMC?

- It is recommended to check with GMC or the National Highway Traffic Safety Administration (NHTSA) website for any recalls or service bulletins related to the B0101 code. Manufacturers may issue recalls for known safety issues.

10. How can I prevent the OBDII code B0101 GMC from appearing in the future?

- Regular maintenance and inspections of the airbag system, including the EFS and wiring, can help prevent the B0101 code from appearing. Addressing any warning signs or issues promptly can help maintain the safety features of your vehicle.