AutoCodes – Generic – B1786

B1786 Code - Mirror Passenger Down Circuit Failure

Quick Answer

The Body Control Module (BCM) monitors the Mirror Passenger Down Motor. Common causes include Faulty Mirror Passenger Down Motor, Mirror Passenger Down Motor harness is open or shorted, Mirror Passenger Down Motor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1786 indicates Mirror Passenger Down Circuit Failure.
Common causes: Common causes include Faulty Mirror Passenger Down Motor, Mirror Passenger Down Motor harness is open or shorted, Mirror Passenger Down Motor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 4,854

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Oct 16, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1786 Description

The Body Control Module (BCM) monitors the Mirror Passenger Down Motor. The BCM sets the OBDII code when the Mirror Passenger Down Motor is not to factory specifications.

OBDII Code B1786 - Mirror Passenger Down Circuit Failure - AutoCodes.com — B1786 Code - Mirror Passenger Down Circuit Failure

What does this mean?

What are the Possible Causes of the DTC B1786?

Faulty Mirror Passenger Down Motor
Mirror Passenger Down Motor harness is open or shorted
Mirror Passenger Down Motor circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B1786?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1786 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1786 code?

Need more information on how to fix the B1786 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1786 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1786 Lexus — Front Occupant Classification Sensor Right Collision Detection
B1786 Scion — Front Occupant Classification Sensor Right Collision Detection
B1786 Toyota — Front Occupant Classification Sensor Right Collision Detection

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1786 Code

1. What are the common symptoms of OBDII code B1786 (Mirror Passenger Down Circuit Failure)?

- Common symptoms include the passenger-side mirror not adjusting properly or failing to move up or down as intended.

2. What are some possible causes of OBDII code B1786?

- Potential causes could include faulty mirror adjustment switch, damaged wiring or connectors in the mirror circuit, or a malfunctioning mirror motor.

3. How can I diagnose the Mirror Passenger Down Circuit Failure related to code B1786?

- To diagnose this issue, you can start by checking the mirror adjustment switch for proper functionality and inspecting the wiring and connectors for any signs of damage or corrosion.

4. Can a DIY enthusiast repair OBDII code B1786 at home?

- Depending on the root cause of the issue, a DIY enthusiast may be able to repair B1786 by replacing a faulty mirror switch, fixing damaged wiring, or replacing a malfunctioning mirror motor.

5. Is it safe to drive with OBDII code B1786 active?

- While driving with code B1786 active may not pose an immediate safety risk, it's recommended to address the issue promptly to ensure proper functionality of the passenger-side mirror for visibility and safety.

6. Will resetting the OBDII code B1786 resolve the Mirror Passenger Down Circuit Failure issue?

- Resetting the code may temporarily clear the warning light, but it will not fix the underlying problem causing the Mirror Passenger Down Circuit Failure.

7. How much does it typically cost to repair OBDII code B1786?

- The cost of repairing B1786 can vary depending on the specific cause of the issue, but it may range from a simple DIY fix to a more involved repair involving professional assistance.

8. Are there any preventive measures to avoid OBDII code B1786 in the future?

- Regularly inspecting the mirror adjustment system, keeping an eye out for any signs of trouble, and addressing any issues promptly can help prevent the recurrence of code B1786.

9. Can extreme weather conditions contribute to OBDII code B1786 being triggered?

- Yes, extreme weather conditions such as excessive heat or moisture can potentially damage the mirror circuit components and lead to the triggering of code B1786.

10. Are there any specific vehicle makes or models more prone to experiencing OBDII code B1786?

- While code B1786 can affect various vehicle makes and models, certain car brands or models with complex mirror adjustment systems may be more susceptible to this particular issue.