AutoCodes – Cadillac – B1591 Cadillac

B1591 Cadillac Code - Mirror Vertical Position Sensor Voltage

Quick Answer

The Left Mirror and the Right Mirror Vertical Position Sensors are Potentiometers. Common causes include Faulty Left Mirror or Right Mirror, Left Mirror or Right Mirror harness is open or shorted, Left Mirror or Right Mirror 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: B1591 Cadillac indicates Mirror Vertical Position Sensor Voltage.
Common causes: Common causes include Faulty Left Mirror or Right Mirror, Left Mirror or Right Mirror harness is open or shorted, Left Mirror or Right Mirror 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 1,873

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 May 19, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1591 Cadillac Description

The Left Mirror and the Right Mirror Vertical Position Sensors are Potentiometers. The Driver Door Module (DDM) and the Passenger Door Module (PFDM) determine the vertical position of the mirrors based on the signal voltage from these sensors. The code will be set when the signal voltage of the mirror vertical position sensor is above or below the range limits, within 10%, for 30 seconds in the requested position. The voltage range limits depend upon what the actual voltage of the 5 volt reference circuit is, and will vary from vehicle to vehicle and from module to module.

OBDII Code B1591 Cadillac - Mirror Vertical Position Sensor Voltage - AutoCodes.com — B1591 Cadillac Code - Mirror Vertical Position Sensor Voltage

What does this mean?

What are the Possible Causes of the DTC B1591 Cadillac?

Faulty Left Mirror or Right Mirror
Left Mirror or Right Mirror harness is open or shorted
Left Mirror or Right Mirror circuit poor electrical connection

How to Fix the DTC B1591 Cadillac?

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 B1591 Cadillac 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 B1591 Cadillac Code

1. What does the OBDII code B1591 mean on a Cadillac?

Code B1591 indicates an issue with the mirror vertical position sensor voltage, typically related to the side-view mirror's ability to adjust vertically.

2. What are the common symptoms of the B1591 code?

Symptoms include the inability to adjust the mirror vertically, erratic mirror movement, or the mirror not responding to input from the adjustment controls.

3. What causes the B1591 code to appear?

The code is usually caused by a faulty mirror vertical position sensor, wiring issues, a damaged mirror motor, or a malfunction in the mirror control module.

4. Can a bad connection cause the B1591 code?

Yes, loose or corroded electrical connections in the mirror's wiring harness can trigger this code.

5. How is the B1591 code diagnosed?

A technician will use a scan tool to confirm the code, inspect the wiring and connectors, and test the mirror vertical position sensor for proper voltage and functionality.

6. Can I still drive my Cadillac with the B1591 code?

Yes, the vehicle is safe to drive, but the affected mirror may not adjust properly, which could reduce visibility and convenience.

7. How do I fix the B1591 code on my Cadillac?

Repairs may involve replacing the mirror vertical position sensor, repairing damaged wiring, or replacing the mirror assembly if the motor or sensor is integrated.

8. How much does it cost to fix the B1591 code?

Repair costs can vary, but replacing the sensor or repairing wiring typically costs between $100 and $300, depending on labor rates and parts pricing.

9. Can I clear the B1591 code without fixing the issue?

Clearing the code without addressing the underlying problem will likely result in the code returning, as the issue is still present.

10. Is the B1591 code common on all Cadillacs?

This code is specific to Cadillac models with powered side-view mirrors and may occur more frequently in vehicles with advanced mirror adjustment features.