B1806 – OBD-II DTC

OBD-II DTC B1806 – Lamp Tail Output Circuit Failure

DTC B1806 meaning

DTC B1806 refers to a diagnostic trouble code indicating a failure in the lamp tail output circuit. This code is typically associated with the vehicle’s body control module (BCM) and is related to the operation of the tail lights. When the BCM detects an issue with the tail lamp circuit, it triggers this code to alert the technician of a potential malfunction.

DTC B1806 symptoms

Common symptoms associated with DTC B1806 may include:

• Tail lights not functioning or flickering
• Dashboard warning lights illuminated
• Inconsistent operation of other lighting systems
• Possible issues with related electrical components

DTC B1806 causes

Several factors can lead to the triggering of DTC B1806, including:

• Faulty tail light bulbs
• Damaged or corroded wiring in the tail lamp circuit
• Defective body control module (BCM)
• Poor ground connections
• Short circuits or open circuits in the tail lamp circuit

DTC B1806 seriousness

The seriousness of DTC B1806 can vary depending on the specific symptoms and the vehicle’s overall condition. While it may not pose an immediate safety risk, non-functional tail lights can lead to visibility issues for other drivers, increasing the risk of accidents. Therefore, it is important to address this code promptly to ensure proper vehicle lighting and compliance with safety regulations.

How to diagnose DTC B1806

To diagnose DTC B1806, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the B1806 code.
2. Inspect the tail light bulbs for any signs of damage or failure.
3. Check the wiring and connectors in the tail lamp circuit for corrosion or damage.
4. Test the body control module for proper operation.
5. Examine ground connections for continuity and security.
6. Perform a visual inspection of the entire circuit for shorts or opens.

How to fix DTC B1806 step-by-step instructions

To fix DTC B1806, follow these steps:

1. Replace any faulty tail light bulbs.
2. Repair or replace damaged wiring and connectors in the tail lamp circuit.
3. Test and, if necessary, replace the body control module.
4. Ensure all ground connections are clean, secure, and free of corrosion.
5. Check for shorts or opens in the circuit and repair as needed.
6. Clear the DTC using an OBD-II scanner and test the system to ensure the issue is resolved.

How to erase DTC B1806

To erase DTC B1806, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the vehicle’s ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the vehicle to verify that the code does not reappear.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.