Code Definition

B1787 — Mirror Passenger Down Circuit Open

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

About B1787

B1787 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 B1787 is stored, the module has detected an open (broken or disconnected) electrical path 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.

B1787 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 B1787 is set when the module commands the passenger mirror to move down but detects an open circuit on the down drive output, meaning no current is flowing through the motor winding when voltage is applied. The mirror motor is a small reversible DC motor driven through H bridge outputs in the module, and an open in the wiring, connector, or motor winding interrupts the load circuit. When this code is set, the passenger mirror will fail to tilt do...

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