What is Canbus? Why You Need It?

In today's era of continuous advancements in automotive lighting technology, many car owners opt to upgrade their traditional halogen headlights to advanced LED headlights. However, this upgrading process may trigger a series of compatibility issues, with one key solution being the use of canbus. Canbus play a crucial role in the upgrade of automotive lighting, addressing not only the mismatch between electrical systems but also ensuring the proper functioning of the new LED headlights.

In this blog, we will delve into the role of canbus, why they are essential in the upgrade of automotive lighting, and how they become effective problem solvers for compatibility issues. Let's explore the technological mysteries closely tied to vehicle illumination.

What Is Canbus?

Canbus, also known as Controller Area Network bus, is designed to enable communication between microcontrollers and devices in applications without a central host. In essence, Canbus checks the operational status of various components in your vehicle. The CANbus system determines the functionality of bulbs by measuring resistance in the circuit and the pulse signals emitted by the lights. This is why, when you replace halogen bulbs with LEDs, the Canbus may trigger a warning light due to the lower voltage of LED bulbs.
Currently, there are three types of decoders: resistor, capacitor, and combination decoders.

1. Resistor Decoder

Traditional halogen bulbs typically operate at 55 watts or below. LEDs are more energy-efficient, requiring only 15-35 watts. This leads the canbus system to believe that your lights might exceed its operational range. Resistors can increase power consumption to deceive the canbus and prevent flickering. The advantages of resistors include their low cost, ease of use, and almost guaranteed functionality in common scenarios. However, a drawback is that resistors generate a significant amount of heat. They need to be installed on metal components and kept at a certain distance from rubber parts.
Pros: Low cost, easy to use
Cons: High power generation, elevated operating temperature

2. Capacitor Decoder

For high-power LED automotive bulbs operating at 45-55 watts or below, flickering is often caused by the canbus' pulse width modulation protocol. In such cases, capacitors can reduce flickering issues by eliminating voltage disturbances. However, capacitors are only suitable for certain car modules, which may limit their effectiveness in addressing the problem.
Pros: Reduction in flickering issues
Cons: Limited applicability to certain cars, substantial limitations

3. Combination Decoder

A combination decoder typically includes resistors, capacitors, and a circuit board. The circuit board is designed to detect canbus protocols, allowing for a plug-and-play experience. This type of decoder can address nearly 90% of flickering issues. It is easy to use, provides signal feedback similar to halogen bulbs, generates low heat, detects pulses from the vehicle's computer, ensures stable power output, and poses fewer safety hazards.
Pros: Plug-and-play, similar signal feedback, low heat generation, pulse signal detection, stable power output
Cons: Higher price

The Role and Importance of Canbus

When do you need a canbus? You might need a canbus for your car when you have installed LED headlights and encounter any of the following issues:
  •  Flickering when the bulbs are turned on.
  •  Displaying headlight errors.
  •  Bulbs staying illuminated even after being turned off.
  •  Abnormally dim light output.

Headlight canbus, is electronic devices designed to address compatibility issues that may arise during the upgrade of some automotive LED lighting systems. These issues may include:
Mismatched Resistance Values: Some vehicles are designed with specific resistor circuits to detect whether the headlights are functioning properly. Traditional halogen headlights use higher resistance values, while LED headlights typically have lower resistance values. If the resistance values do not match when replacing headlights, the vehicle may incorrectly assume that the bulbs are burnt out, leading to flickering or warnings.
Reverse Polarity Issues: Some vehicles' electrical systems require bulbs to operate only in a specific direction of current flow, while LED headlights are usually bi-directional, meaning they have no polarity. This can result in headlights not lighting up correctly or flickering.
The role of headlight decoders is to address these compatibility issues. They simulate the correct resistance values, adjust the direction of the current, or perform other necessary operations to ensure that LED headlights function properly in the vehicle, avoiding incorrect warnings or problems. They ensure the proper functioning of the headlight system, eliminating compatibility issues that may arise when upgrading to LED headlights without affecting the normal operation of the vehicle. Headlight decoders are essential in many vehicles that undergo LED headlight upgrades.
When ordering light bulbs or some led driving lights on the COLIGHT website, there is no need to worry as most products come with canbus compatibility, ensuring better compatibility with your vehicle.


In this blog, we delved into the indispensable role of decoders in the process of upgrading automotive lights. Bulbs or LED headlights that come equipped with decoders allow car owners to effortlessly enjoy the numerous benefits brought by LED lighting, such as increased brightness, lower energy consumption, and extended lifespan, without the concerns of compatibility issues. The intelligent design and widespread applicability of decoders make the upgrade of automotive lights a simpler and more feasible task.