What Does B1643 Mean?
This code indicates the Body Control Module (BCM) has detected an electrical circuit malfunction in the passenger side (right) power mirror control system. The BCM monitors voltage, current, and continuity in the mirror motor circuits and has identified an open circuit, short to ground, short to power, or excessive resistance. This prevents proper operation of the passenger mirror adjustment functions controlled by the right-side circuits.
Common Causes
40%
Damaged or corroded wiring harness between door jamb and mirror assembly due to repeated flexing
30%
Failed mirror motor assembly or internal motor short circuit
20%
Corroded or loose connector at mirror base or BCM connection point
10%
Failed Body Control Module internal mirror control circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of passenger mirror wiring harness in door jamb area for broken, chafed, or pinched wires. Check mirror connector at base of mirror housing for corrosion, moisture intrusion, or loose pins.
2
Step 2: Using a digital multimeter, check for power and ground at the mirror connector with ignition on. Verify 12V power supply and ground integrity (should read less than 0.5 ohms to chassis ground).
3
Step 3: Disconnect mirror connector and measure resistance across mirror motor terminals. Normal reading should be 3-10 ohms depending on manufacturer. Infinite resistance indicates open motor, near-zero indicates shorted motor.
4
Step 4: With mirror disconnected, command mirror operation through scan tool bidirectional controls while monitoring voltage at BCM-side connector. Voltage should toggle between 0-12V during commanded movements to confirm BCM output.
5
Step 5: Check continuity of each wire in the harness from BCM connector to mirror connector. Resistance should be less than 1 ohm per wire. Also check for shorts between wires and shorts to ground (should read infinite resistance).
6
Step 6: After repairs, clear codes, cycle ignition, operate mirror through full range of motion in all directions, and verify code does not return. Perform final scan to confirm no pending or stored codes.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an electrical circuit malfunction in the passenger side (right) power mirror control system. The BCM monitors voltage, current, and continuity in the mirror motor circuits and has identified an open circuit, short to ground, short to pow...
The most common cause of B1643 (Mirror Passenger Right Circuit Failure) is: Damaged or corroded wiring harness between door jamb and mirror assembly due to repeated flexing
Typical repair costs for B1643 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects passenger mirror adjustment convenience features. Repair at your convenience, though proper mirror positioning is important for safe lane changes and backing maneuvers.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1643 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Accessories
Difficulty
Type
Manufacturer
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