Code Definition

B1794 — Lamp Headlamp Low-Beam Circuit Failure

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

About B1794

B1794 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 B1794 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

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.

B1794 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 low beam headlamp circuit by measuring current draw and voltage on the output side of the headlamp driver. DTC B1794 sets when the BCM detects an electrical fault in the low beam circuit, such as an open circuit, short to ground, or short to power that prevents normal operation. The low beam headlamps may be commanded directly by the BCM through internal solid state drivers, or via a relay controlled by the BCM. When this code is set, the driver will typically notice that one or both low beam headlamps fail to illuminate when commanded, the high beams...

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