OBD-II trouble code
B009C: Left Side Restraints Sensor 6 (Subfault)
The airbag/SRS control module detected a fault with the left-side restraints (impact) sensor 6. Side-impact airbag deployment on that side may be affected, so this needs prompt professional attention.
Quick facts
- System
- Body
- Category
- Airbag / SRS Restraints
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $600
- DIY difficulty
- Shop recommended
What does B009C mean?
B009C is a body (B) code stored by the airbag control module. It is a hexadecimal code — the character after B009 is the letter C, not a number — and its SAE-generic definition is 'Left Side Restraints Sensor 6,' referring to one of the satellite impact (crash) sensors on the left side of the vehicle that tell the module when and how hard a side impact is occurring. It caps the left-side satellite set that runs B0091/B0092/B0093 (Sensors 1-3) and B009A/B009B (Sensors 4-5), and it is the left-side mirror of B009F (Right Side Restraints Sensor 6). These sensors are typically mounted in the door, B-pillar, C-pillar, or rocker area and feed the control module the data it uses to decide whether to fire the side and curtain airbags and the seat-belt pretensioners. A sixth sensor on one side appears only on vehicles with the most extensive side-impact coverage, so confirm the exact sensor and location against your make's service data before assuming it is fitted.
Unlike a deployment-loop code, a restraints-sensor code is about the module receiving valid data from the impact sensor rather than a firing circuit. The module sets B009C when the sensor's signal, supply, or ground is out of specification — an open or short in the wiring, a corroded or backed-out connector, a failed sensor, or a supply/ground problem shared with other sensors. A symptom byte appended to the code narrows down the exact fault. Because side sensors live low in the door or rocker where they meet road spray, car-wash water, and door-hinge harness flex, moisture intrusion and flexing wiring are common causes; if several left-side sensor codes set together, suspect a shared power, ground, or connector rather than several dead sensors.
This is a supplemental restraint fault, not a driveability fault: the vehicle drives normally, but side-impact protection on the left may not perform as designed, and airbag circuits carry a small risk of unintended deployment when mishandled. SRS diagnosis and repair should be performed by a qualified technician who can safely disable the system, and the fault should not be left unrepaired.
Common causes
- Corroded or water-intruded connector at the left-side impact sensor
- Damaged or chafed wiring in the door/rocker or pillar harness, often from door-hinge flex
- Failed left-side restraints (impact) sensor
- Open, short, or high resistance in the sensor's signal, supply, or ground circuit
- Shared power or ground fault affecting multiple left-side sensors
- Prior side-impact damage or repair that disturbed the sensor or its wiring
Symptoms
- Airbag / SRS warning light on
- Stored B009C fault (often with a symptom byte) in the restraints module
- No effect on engine or driving performance
- Fault that may appear or clear with door movement or after exposure to water
Diagnostic steps
- 1.Use a scan tool that can access the airbag/SRS module and record B009C with its full symptom byte and any companion left-side sensor codes such as B009A or B009B.
- 2.Locate the left-side restraints sensor 6 for the specific make and model — position varies (door, pillar, or rocker) and only some vehicles have a sixth sensor.
- 3.With the system safely disabled per service procedure, inspect the sensor connector for moisture, corrosion, or backed-out terminals.
- 4.Inspect the door/rocker harness for chafing or flex damage, working the door while monitoring for an intermittent fault.
- 5.Check the sensor's power and ground against specification; a shared supply/ground fault can set several sensor codes at once.
- 6.If wiring, connector, power, and ground all check out, the sensor itself is the likely failure.
- 7.Repair the wiring/connector or replace the sensor, then clear codes and confirm the SRS light stays off.
Repair cost
$100 – $600
Cleaning or repairing a corroded connector can be inexpensive, while a failed side impact sensor typically runs a few hundred dollars including diagnosis. SRS diagnostic time is usually $100-$200, and a crash-sensor replacement with the required system checks generally falls in the $200-$500 range. SRS work should be done by a qualified technician.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with airbag / srs crash sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.