Airbag code
B0100: Front impact sensor circuit fault
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $90 | $400 |
| Labor: 1.2 to 2 hours × $125 to $175 an hour | $150 | $350 |
| Fees: shop supplies, disposal, diagnostics | $0 | $50 |
| Total, rounded | $240 | $800 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, airbag / occupant sensor replacement. Which repair your car needs depends on a proper diagnosis.
The airbag computer is not getting a good signal from one of the front crash sensors. Those sensors sit behind the bumper or at the radiator support, where water, road salt and small impacts can reach them. This is the usual meaning, but it varies by make, so check the scan tool or manual.
- Safe to drive?
- No, get it looked at first
- Most common cause
- Failed or loose front crash sensor
The airbag system may be turned off, so the airbags may not deploy in a crash. Get it checked soon and avoid putting children in the front seat.
What you may notice
- Airbag light on
- Sensor behind the bumper may look damaged
- No other symptoms
Common causes, most likely first
- Failed or loose front crash sensor
- Damaged wire or connector near the bumper
- Rust or water at the connector
- Past collision damage
- Airbag module fault
Check this first
Look at the sensor behind the front bumper or near the radiator support for damage, water, or a loose plug.
Other repairs that sometimes fix B0100
| Repair | Typical range, Boston |
|---|---|
| CAN bus wiring repair | $190 to $1,275 |
| ECU / engine control module replacement | $430 to $2,350 |
| Diagnostic scan (check engine light) | $60 to $290 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
B0100 questions
Do crash sensors wear out?
They rarely wear out, but road damage, water and corrosion can hurt them. A sensor that has been through a flood or a hit is the one most likely to fail.
Is bumper damage related?
Yes. Even a small parking bump can move or crack a sensor or its bracket. If the light came on after a minor hit, tell the shop so they check the sensors first.
Can I drive until it is fixed?
The car drives, but the airbags may not work in a crash. Get it checked soon. If the repair is a loose plug or a bracket, it may cost little, but do not leave it for months.
How much does it cost to fix B0100?
The most common fix, airbag / occupant sensor replacement, has a typical range of $240 to $800 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
Related codes
- B0001: Driver airbag circuit fault
- B1000: Airbag control module internal fault
- B1421: Restraint circuit fault (varies by make)
More airbag codes
Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.