Code Definition

B1104 — Accessory Power Failure

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

About B1104

B1104 is a manufacturer-specific body diagnostic trouble code recorded for Subaru vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

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.

B1104 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 Integrated Unit (BIU) monitors the accessory (ACC) power feed circuit to ensure correct voltage is present when the ignition switch is in the ACCESSORY or RUN position. DTC B1104 is logged when the BIU detects either an open circuit (no voltage) or a short to ground (voltage pulled low) on the ACC feed for longer than the allowable detection time, indicating loss of accessory feed integrity. The BIU uses the ACC signal to gate features that are designed to operate in accessory mode, so a failure of this input can prevent audio, climate blower, power windows after ignition off, and sim...

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