Code Definition

B1786 — Mirror Passenger Down Circuit Failure

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

About B1786

B1786 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 B1786 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.

B1786 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 or Driver Door Module monitors the passenger side power mirror motor circuits, including the down direction drive output. DTC B1786 sets when the module detects an electrical fault on the passenger mirror down movement circuit, such as an open circuit, short to ground, short to power, or excessive current draw when the down command is active. The mirror motor is a small reversible DC motor driven through H bridge outputs from the module, with the polarity of supply reversed to change movement direction. When this code is set, the passenger mirror may fail to tilt downwa...

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