B1779

What does B1779 mean?

B-code B1779 means "Mirror Driver Down Circuit Open". It is a manufacturer-specific diagnostic trouble code (DTC) in the body electronics. The circuit is open (broken/disconnected), meaning no electrical continuity exists in the mirror driver down circuit open wiring path. This warning should be addressed within the next few days to avoid further damage. This code applies to OBD-II compliant electric and hybrid vehicles.

Possible Causes

• Broken, frayed, or corroded wiring harness causing an open circuit
• Disconnected or damaged electrical connector at the sensor or module
• Faulty sensor or actuator with an internal open circuit
• Corrosion at connector pins due to moisture or road salt exposure

Recommended Actions

1. 1 Avoid aggressive driving and schedule a diagnostic appointment within the next 1–3 days
2. 2 Scan for all DTCs with an OBD-II scanner — note any related codes stored alongside B1779
3. 3 Inspect wiring harness and connectors for breaks, corrosion, or disconnection in the affected circuit
4. 4 Use a multimeter to test for continuity in the signal wire from sensor to module
5. 5 Clear the DTC, road-test the vehicle, and re-scan to confirm whether the fault returns
6. 6 If the fault persists after inspection and clearing, consult an EV-certified technician for component replacement

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