Code Definition

B2502 — LF LAMP LOW BEAM CIRCUIT Short to Battery

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

About B2502

B2502 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.

When B2502 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and a signal or supply voltage lower than the expected operating range.

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 B2502 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

The Body Control Module (BCM) or front lighting module controls the left front low beam headlamp by switching battery voltage or ground to the bulb. DTC B2502 is set when the BCM detects that the left front low beam control line is shorted to battery voltage, meaning the wire is pulled to system voltage when the BCM is commanding the output OFF. The BCM monitors feedback on the output line to verify its own driver state; when external voltage is feeding into the circuit the BCM disables the driver to protect itself and logs this code. With this fault present the left low beam may stay on conti...

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