B0101 on Toyota: How to Diagnose & Fix
Electronic Frontal Sensor 2 Malfunction
1 Toyota model · 1 documented issue · 1 critical
B0101 on Toyota by model: symptoms, diagnosis and fix
Takata airbag inflators can explode during deployment, sending metal shrapnel at occupants. This is a critical safety recall affecting millions of vehicles. The driver and/or passenger airbag inflators need replacement. 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)
- 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: DO NOT DRIVE Advisory for Certain 2003-2005 Models with Recalled Takata Airbagsmanufacturer
B0101 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 B0101 mean on a Toyota?
B0101 stands for "Electronic Frontal Sensor 2 Malfunction." This is a safety-system (SRS/airbag) code, so it should be taken seriously. Modern cars use frontal impact sensors that detect a crash and tell the airbag control module when and how to deploy the airbags. B0101 indicates the airbag (SRS) control module detected a malfunction or circuit fault with frontal impact sensor 2 — meaning the sensor or its wiring isn't reporting correctly, so the module may not be able to rely on it in a collision. This typically lights the airbag warning lamp and can disable airbag deployment until repaired, which is a genuine safety risk in a frontal crash. Note this is a manufacturer-specific code, so the exact sensor location and meaning can vary by make. On Toyota it is documented across 1 model: 4Runner.
What are the most common causes of B0101?
The most common causes of B0101 are: Failed front impact/frontal crash sensor (sensor 2), Damaged, corroded or unplugged sensor wiring/connector, Connector or wiring damage from a prior collision or repair, Water intrusion or corrosion at the sensor connector, Poor ground or open circuit to the sensor, Faulty airbag (SRS) control module, Sensor not properly seated or improperly mounted after service. The specific cause varies by vehicle.
How much does it cost to fix B0101 on a Toyota?
Repair costs vary widely with the root cause and Toyota model; each issue on this page carries its own estimate where one is published.
Looking for B0101 on a different make?
View B0101 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.