AutoCodes – GMC – B2149 GMC

B2149 GMC Code - Outside Rearview Mirror Position Sensor Input Voltage High

Quick Answer

The Memory Mirror Module (MMM) receives inputs from mirror position sensors during these functions: memory recall, memory seat and easy exit. Common causes include Faulty Outside Rearview Mirror Motor, Outside Rearview Mirror Motor harness is open or shorted, Outside Rearview Mirror 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: B2149 GMC indicates Outside Rearview Mirror Position Sensor Input Voltage High.
Common causes: Common causes include Faulty Outside Rearview Mirror Motor, Outside Rearview Mirror Motor harness is open or shorted, Outside Rearview Mirror 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 810

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 Sep 19, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2149 GMC Description

The Memory Mirror Module (MMM) receives inputs from mirror position sensors during these functions: memory recall, memory seat and easy exit. Potentiometers in position sensors vary in resistance as motors move outside rearview mirror. MMM receives a variable voltage input depending on resistance of the potentiometer. During memory set, MMM records voltage across mirrors. During memory recall, MMM moves mirror motors until the voltage across each potentiometer matches recorded the voltage. During normal operation, mirror position sensors are checked against out-of-range limits. Outside rearview mirrors horizontal and vertical position sensor input voltage is 4.75 volts or more.

OBDII Code B2149 GMC - Outside Rearview Mirror Position Sensor Input Voltage High - AutoCodes.com — B2149 GMC Code - Outside Rearview Mirror Position Sensor Input Voltage High

What does this mean?

What are the Possible Causes of the DTC B2149 GMC?

Faulty Outside Rearview Mirror Motor
Outside Rearview Mirror Motor harness is open or shorted
Outside Rearview Mirror Motor circuit poor electrical connection
Faulty Memory Mirror Module (MMM)

How to Fix the DTC B2149 GMC?

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 B2149 GMC 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.

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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 B2149 GMC Code

1. What are the common symptoms of OBDII code B2149 GMC "Outside Rearview Mirror Position Sensor Input Voltage High"?

- The common symptoms include erratic movement of the outside rearview mirror, mirror position not adjusting correctly, and possible mirror position sensor malfunction warning on the dashboard.

2. What can cause the OBDII code B2149 GMC to trigger?

- The code can be triggered by issues such as a faulty outside rearview mirror position sensor, damaged wiring or connectors related to the sensor, or a problem with the mirror control module.

3. How can I diagnose the cause of OBDII code B2149 GMC "Outside Rearview Mirror Position Sensor Input Voltage High"?

- Diagnosis involves visually inspecting the wiring and connectors for any visible damage, testing the mirror position sensor for proper functionality, and checking the mirror control module for any faults.

4. Can I continue to drive my vehicle with the B2149 GMC trouble code?

- It is generally safe to drive the vehicle with this code, but it is recommended to address the issue promptly to prevent further damage to the mirror system.

5. How can I repair OBDII code B2149 GMC myself?

- DIY repairs may involve replacing the outside rearview mirror position sensor, repairing or replacing damaged wiring or connectors, or resetting the mirror control module if needed.

6. Will resetting the OBDII code B2149 GMC make it go away permanently?

- Resetting the code may temporarily clear the warning light, but if the underlying issue causing the code is not addressed, the code is likely to reappear.

7. Is it necessary to visit a mechanic for OBDII code B2149 GMC diagnosis and repair?

- While some DIY repairs are possible, consulting a mechanic is recommended for a proper diagnosis and repair of the outside rearview mirror position sensor issue.

8. Can extreme weather conditions affect the outside mirror position sensor and trigger the B2149 GMC trouble code?

- Yes, extreme weather conditions such as heavy rain or snow can potentially damage the sensor or its wiring, leading to the code being triggered.

9. How do I prevent OBDII code B2149 GMC from occurring in the future?

- Regular inspection and maintenance of the outside rearview mirror system, keeping it clean and free from debris, can help prevent issues with the mirror position sensor and avoid triggering the code.

10. Are there any recalls or technical service bulletins related to OBDII code B2149 GMC for specific GMC models?

- It is recommended to check with an authorized GMC dealership or visit the manufacturer's website to see if there are any recalls or technical service bulletins related to this specific trouble code for your GMC vehicle.