Damaged, pinched or corroded wiring or connector under the driver seat; Poor connection at the seat connector, often disturbed by seat movement or items stored under the seat; Faulty occupant classification sensor or sensor mat in the driver seat; Seat work or a seat cover or accessory fitted that has affected the sensor, or a sensor needing initialisation after seat work; Low supply voltage or a poor earth affecting the SRS circuit; Faulty SRS control unit or its software.

B00B3

Driver Seat Occupant Classification Sensor D.

Generic
Body
Generic code
Medium severity

How this code is built

B: SystemBody
0: Defined bySAE, the same on every car
0: AreaBody area 0
B3: FaultThe specific fault in that area

What it means

B00B3 is defined as a fault with Driver Seat Occupant Classification Sensor D, part of the occupant detection inputs to the airbag (SRS) control unit. The control unit has seen a signal from this sensor that is missing, out of range or implausible, or has lost communication with it. The exact sensor layout and what 'D' refers to vary by model, so check the manufacturer's data for the vehicle.

Symptoms

Airbag warning light on
Driver seat occupancy or airbag status indicator showing incorrectly
Seat belt reminder chime or light behaving wrongly or not working
Driver airbag may be disabled or its deployment level affected by the system
Fault returns after being cleared, often after the seat is moved or loaded

Possible causes

Damaged, pinched or corroded wiring or connector under the driver seatlikely
Poor connection at the seat connector, often disturbed by seat movement or items stored under the seatlikely
Faulty occupant classification sensor or sensor mat in the driver seatpossible
Seat work or a seat cover or accessory fitted that has affected the sensor, or a sensor needing initialisation after seat workpossible
Low supply voltage or a poor earth affecting the SRS circuitpossible
Faulty SRS control unit or its softwarerare

How to diagnose

Read all stored codes and freeze frame data, noting whether the fault is current or stored and whether other SRS codes are present
Check for water ingress, spilled drinks, aftermarket seat covers or objects under or around the driver seat
Visually inspect the seat wiring and connectors for chafing, pinching, bent pins or corrosion, following the manufacturer's SRS safety precautions (battery disconnected and the required wait time observed)
Check battery condition and the supply and earth to the SRS system
Move the seat through its full range and wiggle the harness while monitoring live data for the sensor signal
Compare the sensor live data empty and occupied against the manufacturer's specification, as procedures and values vary by model
Test the sensor and circuit resistance only using the manufacturer's approved procedure, and never probe SRS connectors otherwise

How to fix

Repair or replace damaged wiring and connectors under the seat, using the manufacturer's approved repair method
Clean and secure the seat connector, and re-route the harness so it is not pinched by the seat mechanism
Replace the faulty occupant classification sensor or seat component, and carry out any initialisation the manufacturer requires after fitting
Remove or replace any seat cover or accessory that interferes with the sensor
Correct battery or earth faults affecting the SRS circuit
Replace or update the SRS control unit only after the wiring and sensor have been proven good and the manufacturer confirms it

Can I keep driving?

Medium severity

The car can usually still be driven, but the airbag system may not protect the driver as designed, so get it inspected soon. Avoid long journeys until it is repaired.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.