Code Definition

B1798 — Lamp Turn Signal Front Output Circuit Failure

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

About B1798

B1798 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 B1798 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.

B1798 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) controls the front turn signal lamp output and monitors the circuit for proper operation by measuring current draw and feedback voltage when the lamp is commanded on. DTC B1798 sets when the BCM detects an electrical fault on the front turn signal output, such as an open circuit, short to ground, or short to battery, that prevents the lamp from operating within expected parameters. On most modern vehicles the turn signal output is shared with the hazard warning function and may also incorporate a daytime running light or position lamp duty cycle on the same filame...

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