AutoCodes – Generic – B1591

B1591 Code - Autolamp Delay Decrease Circuit Failure

Quick Answer

The Body Control Module (BCM) monitors the Autolamp Delay. Common causes include Faulty Autolamp Delay, Autolamp Delay harness is open or shorted, Autolamp Delay 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 indicates Autolamp Delay Decrease Circuit Failure.
Common causes: Common causes include Faulty Autolamp Delay, Autolamp Delay harness is open or shorted, Autolamp Delay 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 5,782

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 05, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code B1591 Description

The Body Control Module (BCM) monitors the Autolamp Delay. The BCM sets the OBDII code when the Autolamp Delay is not to factory specifications.

OBDII Code B1591 - Autolamp Delay Decrease Circuit Failure - AutoCodes.com — B1591 Code - Autolamp Delay Decrease Circuit Failure

What does this mean?

What are the Possible Causes of the DTC B1591?

Faulty Autolamp Delay
Autolamp Delay harness is open or shorted
Autolamp Delay circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B1591?

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 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 B1591 code?

Need more information on how to fix the B1591 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1591 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1591 Buick — Mirror Vertical Position Sensor Voltage
B1591 Cadillac — Mirror Vertical Position Sensor Voltage
B1591 Chevrolet — Mirror Vertical Position Sensor Voltage
B1591 GMC — Mirror Vertical Position Sensor Voltage
B1591 Lexus — No Response From Audio HU
B1591 Toyota — No Response From Audio HU

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 Code

1. What are common symptoms of OBDII code B1591 (Autolamp Delay Decrease Circuit Failure)?

- Common symptoms include the automatic lamps failing to delay turning off, or the autolamp system not functioning as intended.

2. What can cause OBDII code B1591 to trigger?

- This code is typically triggered by issues with the autolamp delay decrease circuit, such as wiring faults, a faulty autolamp sensor, or a malfunctioning control module.

3. How can I diagnose the cause of OBDII code B1591?

- To diagnose the issue, you can perform a visual inspection of the autolamp system wiring, test the autolamp sensor for proper functionality, and use a diagnostic scanner to check for specific circuit faults.

4. Is it safe to continue driving with OBDII code B1591 present?

- While the code may not affect the overall drivability of the vehicle, it is recommended to address the issue promptly to ensure the autolamp system operates correctly.

5. Can I repair OBDII code B1591 myself?

- Depending on your automotive repair skills, you may be able to address the issue yourself by checking and repairing any wiring faults, replacing a faulty autolamp sensor, or resetting the control module.

6. How much does it typically cost to fix OBDII code B1591 at a repair shop?

- The cost of repair can vary depending on the cause of the issue and the labor rates of the repair shop. It's advisable to obtain quotes from different shops for an accurate estimate.

7. Will resetting the OBDII code B1591 resolve the issue temporarily?

- Resetting the code may temporarily clear the warning light, but if the underlying issue is not fixed, the code is likely to reappear once the system detects the fault again.

8. Can extreme weather conditions affect the autolamp delay decrease circuit and trigger OBDII code B1591?

- Yes, extreme weather conditions can potentially damage the wiring or components of the autolamp system, leading to the triggering of OBDII code B1591.

9. Are there any preventive maintenance tips to avoid OBDII code B1591 in the future?

- Regularly inspecting the autolamp system components, ensuring proper wiring integrity, and keeping the system clean from debris can help prevent issues that trigger OBDII code B1591.

10. Will OBDII code B1591 cause the vehicle to fail an emissions test?

- OBDII code B1591 is related to the autolamp system and is unlikely to cause the vehicle to fail an emissions test. However, it is important to address the issue for overall vehicle safety and functionality.