Code Definition

B1909 — Airbag Crash Sensor #2 Ground Circuit Short To Ground

System: Body  |  Type: Manufacturer-Specific  |  Make: Generic

About B1909

B1909 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1909 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1909 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Restraints Control Module (RCM, also called the Airbag Control Module or SRS module) provides and monitors a controlled ground or signal return reference to each remote crash sensor. On many SRS designs this return is not a direct chassis ground but a sensed pin held at a known low reference voltage by the RCM, allowing the module to detect any unintended path to chassis. DTC B1909 sets when the RCM detects that the ground or return wire to Crash Sensor #2 has been pulled below the expected reference voltage by an unwanted connection to chassis ground somewhere along the conductor, bypassi...

Join TaT to view the complete code information and diagnostic details.

Quick Facts