Code Definition

B1309 — Power Door Lock Circuit Short To Ground

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

About B1309

B1309 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 B1309 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

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.

B1309 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 Body Control Module (BCM) or a dedicated Door Control Module drives the power door lock actuators using protected H bridge outputs that reverse polarity to lock or unlock the doors. The lock actuators are typically reversible DC motors or solenoid plungers integrated into the latch assembly, switched on for a short pulse of around half a second by the controlling module each time a lock or unlock command is processed. DTC B1309 sets when the controlling module detects a short to ground on one of its lock or unlock drive circuits, indicating that the output is being pulled to ground externa...

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