Code Definition

B2490 — UNDERHOOD LAMP OUTPUT CIRCUIT Short to Battery

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

About B2490

B2490 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 B2490 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.

Because B2490 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 B2490 is set when the BCM detects battery voltage on the underhood lamp output wire at a time when it should not be present, indicating a short to battery in the harness, the lamp assembly, or an aftermarket installation. The BCM monitors the actual voltage on its lamp output line and compares it against the commanded state, and may disable the affected driver as a protective measure when an unexpected voltage is detected. When this code is set, the underhood la...

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