AutoCodes – Generic – B2151

B2151 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: B2151 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 5,352

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 B2151 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 B2151 - Outside Rearview Mirror Position Sensor Input Voltage High - AutoCodes.com — B2151 Code - Outside Rearview Mirror Position Sensor Input Voltage High

What does this mean?

What are the Possible Causes of the DTC B2151?

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 B2151?

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 B2151 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 B2151 code?

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Information for Specific Makes

B2151 Buick — Outside Rearview Mirror Position Sensor Input Voltage High
B2151 Cadillac — Outside Rearview Mirror Position Sensor Input Voltage High
B2151 Chevrolet — Outside Rearview Mirror Position Sensor Input Voltage High
B2151 GMC — Outside Rearview Mirror Position Sensor Input Voltage High

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 B2151 Code

1. What are the common symptoms of OBDII code B2151 (Outside Rearview Mirror Position Sensor Input Voltage High)?

The common symptoms of code B2151 include erratic movement of the outside rearview mirror, mirror position not adjusting properly, and the mirror not responding to controls.

2. What are the possible causes of OBDII code B2151?

The potential causes of code B2151 include a faulty outside rearview mirror position sensor, damaged wiring or connectors in the mirror system, or a malfunction in the mirror control module.

3. How can I diagnose OBDII code B2151?

Diagnosing code B2151 involves using a scan tool to retrieve the trouble code, inspecting the wiring and connectors in the mirror system, testing the mirror position sensor, and checking the mirror control module for proper operation.

4. Can OBDII code B2151 be triggered by a blown fuse?

Yes, a blown fuse in the mirror circuit can also trigger code B2151. Make sure to check the fuse related to the outside rearview mirror system before proceeding with further diagnosis.

5. Is it safe to drive with OBDII code B2151?

It is generally safe to drive with code B2151, but it is recommended to address the issue promptly to ensure proper functionality of the outside rearview mirror.

6. How can I repair OBDII code B2151?

Repairing code B2151 may involve replacing the faulty outside rearview mirror position sensor, repairing or replacing damaged wiring or connectors, or addressing any issues with the mirror control module.

7. Can I reset OBDII code B2151 without making any repairs?

Resetting the code without addressing the underlying issue may temporarily turn off the check engine light, but the problem will likely reoccur. It is best to diagnose and repair the cause of the code.

8. Are there any DIY tips for troubleshooting OBDII code B2151?

DIY tips for troubleshooting code B2151 include visually inspecting the mirror system for any visible damage, checking the fuse related to the mirror system, and ensuring the mirror control switch is functioning correctly.

9. Can extreme weather conditions affect OBDII code B2151?

Extreme weather conditions, such as excessive heat or moisture, can potentially affect the outside rearview mirror system and trigger code B2151. Ensure the mirror components are properly protected from harsh weather.

10. How long does it typically take to repair OBDII code B2151?

The repair time for code B2151 can vary depending on the specific cause of the issue. Simple fixes like replacing a fuse may take a short time, while more complex repairs involving sensor replacement or module troubleshooting may require more time.