Faulty front crash sensor; Damaged or corroded wiring harness or connector at the sensor; Open or short circuit in the sensor wiring; Poor electrical connection due to loose pins or water intrusion; Failed airbag control module (less common); Impact damage from a previous collision not properly repaired

DTC codes / B01xx · Airbags, seats, doors, lights and comfort systems / B0101

B0101Front Crash Sensor Circuit Malfunction

Q: What does code B0101 mean?

Front Crash Sensor Circuit Malfunction. B0101 indicates that the airbag control module has detected a fault in the front crash sensor circuit, which is responsible for detecting a frontal impact and triggering the airbags and seatbelt pretensioners. The module monitors the sensor's signal voltage and sets this code when the voltage falls outside the expected range or the circuit is open or shorted.

B0101 indicates that the airbag control module has detected a fault in the front crash sensor circuit, which is responsible for detecting a frontal impact and triggering the airbags and seatbelt pretensioners. The module monitors the sensor's signal voltage and sets this code when the voltage falls outside the expected range or the circuit is open or shorted.

SystemBody

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

Airbag warning light illuminated on the dashboard
SRS (Supplemental Restraint System) warning message displayed
Often no symptoms besides the warning light
Airbags may be disabled and will not deploy in a collision
Seatbelt pretensioners may not function
In some vehicles, other safety systems like automatic emergency braking may be disabled

Common causes, most likely first

Faulty front crash sensor
Damaged or corroded wiring harness or connector at the sensor
Open or short circuit in the sensor wiring
Poor electrical connection due to loose pins or water intrusion
Failed airbag control module (less common)
Impact damage from a previous collision not properly repaired

How to diagnose and fix it

Inspect the front crash sensor and its connector for physical damage, corrosion, or loose pins
Check the wiring harness for cuts, chafing, or pinched wires
Measure resistance and voltage on the sensor circuit according to the manufacturer's specifications
Test the sensor with a multimeter or oscilloscope to verify signal output
Replace the front crash sensor if testing confirms it is faulty
Repair or replace damaged wiring and connectors as needed
Clear the code and verify the repair by cycling the ignition and checking for return of the code

Front crash sensor faults often misdiagnosed

A common mistake is replacing the airbag control module when the real problem is a chafed wire in the front bumper area.
The front crash sensor is often located behind the bumper cover, making it vulnerable to water and road debris damage.
Some vehicles use a single sensor for both front crash detection and pedestrian protection, so a fault can affect multiple systems.
After any front-end collision repair, the sensor and its wiring should be inspected even if the airbag did not deploy.
A weak battery or charging system issue can cause intermittent sensor codes, so always check system voltage first.

Can I keep driving with B0101?

It is not safe to drive with an active B0101 code because the airbags may not deploy in a crash. Have the vehicle diagnosed and repaired by a qualified technician before driving, and avoid any frontal impacts.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.