Electronic Front End Sensor 1 Circuit Malfunction (Front Impact Sensor -- SRS/Airbag System)
The B0100 code means the vehicle's onboard diagnostic system has detected: Electronic Front End Sensor 1 Circuit Malfunction (Front Impact Sensor -- SRS/Airbag System). This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
- Estimated cost
- $100-$400 (sensor and labor; wiring repairs at the low end, dealer diagnosis adds cost)
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Common Symptoms
- Airbag/SRS warning light illuminated on the dash
- Code B0100 retrieved with a scan tool capable of reading the SRS/airbag module
- No noticeable change in normal drivability
Probable Causes (Ranked by Likelihood)
- Failed front impact (EFS) sensor — known to fail, including from factory overtightening Very High
- Corroded or water-intruded connector where the EFS plugs into the body harness behind the bumper High
- EFS circuit wiring short to ground/voltage or high resistance (chafed harness at the radiator support) Moderate
- Front-end collision damage or, rarely, a faulty SDM (airbag module) Low
Step-by-Step Diagnostic Procedure
-
Confirm the airbag warning lamp is on and retrieve B0100 with a scan tool capable of reading the SRS/airbag module
-
Inspect the front impact sensor connector at the front structure (typically behind the bumper on the lower radiator support) for corrosion, water intrusion, or a loose connection
-
Never probe SRS circuits with the battery connected -- disconnect the battery and wait per service information before working on any SRS wiring or connector
Common Fixes by Vehicle
What techs usually find when diagnosing B0100 on specific vehicles — tap your vehicle for the fix and the exact part:
2007-2018 Chevrolet Silverado/GMC Sierra easy DIY
Airbag ECU malfunction is often caused by a faulty front impact sensor or corroded connector under the bumper. Inspect the driver-side and passenger-side impact sensor connectors first. Water intrusion from a missing fender liner is the usual root cause on these trucks. If connectors are clean, the SDM (Sensing and Diagnostic Module) itself may need replacement. GM TSB #16-NA-076 covers this.
Labor: 30-45 min2009-2019 Ford F-150/F-250 moderate DIY
Check the clockspring in the steering column first -- it connects the airbag module and fails with age. Symptoms include airbag light plus horn and steering wheel button failures. If the clockspring is fine, inspect the passenger seat occupant sensor mat. Ford extended warranty on the occupant sensor for some 2009-2014 models (SSM 47240).
Labor: 1-2 hours2007-2017 Toyota Camry/Corolla moderate DIY
Toyota airbag ECU codes are commonly triggered by a faulty spiral cable (clockspring) or a driver-side airbag connector that works loose. Start by reseating the yellow airbag connectors under the seats -- these vibrate loose over time. If B0100 persists, the airbag ECU behind the center console may need replacement. Always disconnect the battery and wait 90 seconds before working on airbag circuits.
Labor: 1-2 hoursFrequently Asked Questions
Is it safe to drive with B0100?
The vehicle drives normally, but the airbag system may not deploy correctly in a frontal crash, so the repair should be made promptly.
What usually fails to cause B0100?
Most commonly the impact sensor itself or its connector/wiring at the front structure.
Will the airbag light be on with B0100?
Yes, typically the airbag/SRS warning light will be illuminated while this code is active.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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