Code Definition

B1321 — Driver Door Ajar Circuit Short To Battery

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

About B1321

B1321 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 B1321 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.

B1321 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) sets DTC B1321 when it detects that the driver door ajar input is being held at battery voltage instead of toggling between its expected open and closed states. The driver door ajar switch normally pulls the input to ground when the door is open and lets it float to a reference voltage when the door is closed, depending on the manufacturer's circuit design. A short to battery on this line forces the input to a fixed high state regardless of door position, and the BCM recognises that the signal cannot be valid. Drivers may report a permanent door ajar warning, the ...

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