Code Definition

B2586 — Headlamp Mode Select Circuit Failure

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

About B2586

B2586 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 B2586 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 B2586 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 headlamp mode select switch is the multiposition control on the dash, instrument panel rotary, or column stalk that lets the driver choose between off, parking lamps, headlamps, and on many vehicles an auto headlamp position. The Body Control Module or Lighting Control Module reads the switch through a discrete circuit or a resistor ladder, decoding the voltage at the input to identify which position the driver has selected. DTC B2586 sets when the controlling module detects a voltage on the headlamp mode select circuit that does not correspond to any valid switch position, or that has dri...

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