Code Definition

B1581 — Dim Panel Increase Input Circuit Short To Battery

System: Body  |  Type: Manufacturer-Specific  |  Make: Generic

About B1581

B1581 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1581 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.

B1581 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Body Control Module (BCM) monitors the panel dimmer increase input circuit, which is the wire from the dimmer increase switch that the BCM uses to brighten the instrument cluster and dashboard illumination. DTC B1581 sets when the BCM detects the dim panel increase input is shorted to battery voltage, meaning the input is reading a permanent high state regardless of switch position. This typically happens when the input wire chafes against a power feed, when an aftermarket accessory has been incorrectly tapped into the circuit, or when the dimmer switch internally fails in a way that ties ...

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