Code Definition

B2489 — UNDERHOOD LAMP OUTPUT CIRCUIT Failure

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

About B2489

B2489 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 B2489 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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 B2489 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) controls the underhood lamp, which provides illumination of the engine bay when the bonnet is open. DTC B2489 is set when the BCM detects a circuit failure on the underhood lamp output, which typically covers an open circuit, short to ground, or short to battery condition that the module cannot distinguish into a more specific sub fault. The BCM monitors the actual voltage on its lamp output line and compares it against the commanded state to detect the fault, and may disable the affected driver as a protective measure. When this code is set, the underhood lamp wi...

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