B1587 – Autolamp Delay Increase Circuit Failure

The ODBII code B1587 indicates a malfunction in the autolamp delay increase circuit, which is responsible for controlling the duration that the vehicle’s lights remain on after the ignition is turned off.

The severity of ODBII code B1587 Autolamp Delay Increase Circuit Failure is generally considered moderate.

Common Causes For: B1586 Dim Panel Decrease Input Circuit Short To Ground

• Faulty autolamp delay module
• Short circuit in the wiring
• Open circuit in the wiring
• Corroded connectors
• Faulty headlight switch
• Malfunctioning body control module (BCM)
• Poor ground connection
• Damaged or frayed wires

Common misdiagnosis for B1587 Autolamp Delay Increase Circuit Failure

• Faulty headlight switch
• Defective body control module (BCM)
• Wiring issues or shorts in the circuit
• Malfunctioning relay
• Incorrectly diagnosed battery or charging system problems
• Issues with the lighting control module
• Faulty sensors related to ambient light detection

Common Troubleshooting Steps

The OBD-II code B1587 refers to a fault in the autolamp delay increase circuit, which is part of the vehicle’s lighting system. This code typically indicates that there is a problem with the circuit responsible for controlling the delay of the autolamps (automatic headlights). Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues.
• Inspect the Wiring and Connectors: Visually inspect the wiring and connectors associated with the autolamp system. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harness leading to the autolamp module and any related components.
• Test the Autolamp Module: If applicable, test the autolamp control module for proper operation. This may involve checking for power and ground at the module and ensuring it is functioning correctly.
• Consult the vehicle’s service manual for specific testing procedures and pinout diagrams.
• Check the Fuses: Inspect the fuses related to the lighting system and the autolamp module. Replace any blown fuses and check if the issue persists.
• Examine the Headlight Switch: Test the headlight switch for proper operation. A faulty switch can cause issues with the autolamp system.
• Ensure that the switch is in the correct position and functioning as intended.
• Verify Ground Connections: Check the ground connections for the autolamp system. Poor ground connections can lead to erratic behavior and circuit failures.
• Test the Delay Circuit: If the vehicle has a specific delay circuit for the autolamps, test it to ensure it is functioning correctly. This may involve checking resistors, capacitors, or other components in the circuit.
• Inspect Related Components: Check other components that may be related to the autolamp system, such as the body control module (BCM) or any sensors that may affect the operation of the autolamps.
• Clear the Code and Test Drive: After performing any repairs or adjustments, clear the trouble code using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional: If the issue persists after performing these troubleshooting steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle make and model. By following these steps, you should be able to identify and resolve the issue related to the B1587 code. Always refer to the vehicle’s service manual for specific diagnostic procedures and specifications.