B0100: How to Diagnose & Fix — Electronic Frontal Sensor 1 Malfunction
3 vehicles · 2 makes
How to diagnose and fix B0100: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Toyota 4Runner · 2010–2016
Takata airbag inflators can explode during deployment, sending metal shrapnel at occupants. This is a critical safety recall affecting millions of vehicles. On the 2010-2016 4Runner, the front passenger airbag inflator needs replacement (NHTSA recall 19V-005; the model years covered depend on the state where the vehicle is registered). Multiple deaths and injuries have been linked to this defect.
Common Symptoms
- Recall notice received
- Airbag warning light (unrelated symptom)
- No symptoms - defect is hidden
How to Fix
Check VIN immediately at NHTSA.gov, SaferCar.gov, or Toyota's recall website. Repairs are free at any Toyota dealer. Do not delay - this is a life-threatening defect. If parts are unavailable, Toyota may provide a loaner vehicle. This recall never expires.
Owner tips & cautions
- WarningThis is a high-severity issue - ignoring it can lead to costly repairs or safety concerns. Address it promptly.
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
- TipSearch Toyota 4Runner forums and owner groups for real-world experiences and DIY guides
- TipGet multiple quotes from independent mechanics - dealer prices can be 2-3x higher for the same repair
- TipCheck NHTSA.gov for active recalls — repairs are performed free at authorized dealers
Sources for this issue (5)
- NHTSA Recall 19V-005: Toyota passenger frontal air bag inflators (incl. 2010-2016 4Runner)government
- Toyota Pressroom: Toyota is conducting final phase of Takata airbag safety recallmanufacturer
- Toyota: Look up Safety Recalls & Service Campaigns by VIN (Takata)manufacturer
- Consumer Reports: Toyota Recall to Replace Airbags Again | Takatamedia
- Toyota 4Runner Forum: Takata Airbag Recallforum
Toyota RAV4 · 2006–2008
NHTSA Recall 14V-168 / Toyota E0M covers certain 2006-2008 RAV4s produced from late July 2005 through early August 2008 and equipped with a seven-channel spiral cable. A flexible flat cable inside the assembly can contact its retainer and wear as the steering wheel is turned. If the driver's-airbag circuit loses connectivity, the SRS warning lamp may illuminate and the driver's frontal airbag can be deactivated, increasing injury risk in a crash. Not every RAV4 in these model years has the affected assembly.
Common Symptoms
- SRS warning lamp remains illuminated after the ignition self-check
- SRS warning lamp fails to illuminate during its normal self-check
- Driver frontal airbag circuit loses connectivity without a guaranteed warning
How to Fix
Check the complete VIN at Toyota's recall lookup or with an authorized Toyota dealer for open campaign E0M / NHTSA 14V-168. For an eligible incomplete vehicle, Toyota replaces the spiral cable assembly with an improved unit at no charge. Until status is confirmed and any open remedy is completed, pay close attention to the SRS lamp's ignition self-check; if it fails to illuminate, stays on or returns after the check period, arrange prompt dealer diagnosis. The lamp can have unrelated causes, and Toyota notes that the recalled condition may exist without a warning, so do not use lamp behavior alone to decide eligibility. Do not disassemble an airbag-equipped steering column without the factory SRS precautions.
Owner tips & cautions
- TipUse the full VIN to distinguish an open E0M recall, a completed campaign and a vehicle that was never in the seven-channel population.
- WarningAn abnormal SRS-lamp check means the airbag system needs prompt diagnosis; do not assume the driver airbag will deploy normally or clear the lamp without finding the cause.
Sources for this issue (3)
Chevrolet Impala · 2000–2005
The 2000-2005 Impala was included in GM's 2014 ignition key recall 14V-400, which covered 5,877,718 vehicles across several GM models. The weight on the key ring and/or road conditions or some other jarring event can cause the ignition switch to move from the "Run" position to the "Accessory" or "Off" position while driving. When this happens, the engine shuts off, the power steering and brake boost are lost, and the airbags may not deploy — all without warning. The issue is exacerbated by heavy key chains that add weight and leverage on the ignition cylinder.
Common Symptoms
- Engine shuts off unexpectedly while driving
- Key turns to accessory position on its own
- Airbag warning light illuminated
- Power steering lost suddenly
- Dashboard goes dark momentarily while driving
- Stalling when hitting bumps or turning
How to Fix
Check the NHTSA recall database (NHTSA.gov) with your VIN — this is recall 14V-400 (GM recall 14350) and the repair is FREE at any GM dealer regardless of mileage or ownership history. The dealer installs two key rings and an insert in the key slot or a cover over the key head on all ignition keys. Until the recall is completed, remove all extra keys and accessories from your key chain — use only the vehicle key with nothing else attached. NEVER ignore this recall; it is a critical safety issue.
Sources for this issue (1)
Find B0100 by make
Browse every documented model and issue for your make.
B0100 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B0100 mean?
B0100 stands for "Electronic Frontal Sensor 1 Malfunction." This is a body code in the airbag (SRS) system indicating a malfunction with electronic frontal impact sensor 1, one of the crash sensors that detects a frontal collision and tells the airbag controller when to deploy. The system runs a self-check on these sensors and their wiring, and when sensor 1 fails to communicate properly, reads out of range, or shows a circuit fault, this code sets and usually lights the airbag warning lamp. Because it affects crash protection, the airbags or seatbelt pretensioners may not deploy as designed until it's fixed. It generally points to a faulty sensor, its wiring/connector, or the airbag control module.
What are the most common causes of B0100?
The most common causes of B0100 are: Faulty frontal impact (crash) sensor, Damaged, open, or shorted sensor wiring, Corroded or unseated sensor connector, Connector damage from a prior collision or repair, Poor ground or power supply to the sensor, Faulty airbag (SRS) control module. The specific cause varies by vehicle.
How much does it cost to fix B0100?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by B0100?
Au7o has documented B0100 across 3 vehicle models from 2 manufacturers: Chevrolet, Toyota.
Join 700+ subscribers following Au7o for vehicle insights and updates.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.