Code Definition

B2129 — Central Lock Feedback Failure

System: Body  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About B2129

B2129 is a generic (obd-ii standard) body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

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.

Because B2129 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

B2129 is set when the body control module (BCM) does not receive valid feedback confirming that the central locking system has reached the commanded lock or unlock position within the expected time window. Many central locking systems include a position feedback contact, a microswitch, or a current monitoring circuit inside the lock actuator that tells the BCM when the lock has actually completed travel. When this feedback either fails to change state during a lock or unlock command, or returns an unexpected value, the BCM concludes that the lock status cannot be confirmed and sets this DTC. W...

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