Code Definition

B1646 — Mirror Passenger Right Circuit Short To Ground

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

About B1646

B1646 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 B1646 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) 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.

B1646 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) or door control module monitors the output driver circuit that controls the right direction movement of the passenger side outside mirror motor. DTC B1646 is set when the module detects that the right direction output is shorted to ground, meaning excessive current is flowing on the output line because the load has effectively been bypassed. The module senses this as an over current condition and disables the affected driver to prevent damage to the output stage. When this code is set, the passenger side mirror typically fails to move to the right, the motor may s...

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