Description

how to check can bus resistance ?

**How to Check CAN Bus Resistance? A Step-by-Step Guide**

If you’re working with vehicles or machines that use CAN (Controller Area Network) bus technology, you know how crucial it is to ensure proper communication between devices. One common issue that can disrupt this communication is incorrect CAN bus resistance. In this article, we’ll explore how to check CAN bus resistance and provide you with some valuable resources to help you troubleshoot CAN bus issues.

**Why is CAN Bus Resistance Important?**

CAN bus resistance is essential to prevent reflections from interfering with data transmissions. A CAN bus has to be terminated on both ends with a 120-ohm resistor to ensure proper signal transmission. If the termination resistor is not present or is faulty, it can cause communication errors, leading to system failures or malfunctions.

**How to Check CAN Bus Resistance**

To check CAN bus resistance, follow these steps:

1. **Disconnect the vehicle battery**: This is a safety measure to prevent any electrical shock or damage to your multimeter.
2. **Disconnect the CAN bus connector**: Unplug the connector from the device.
3. **Measure resistance between CAN HI and CAN LOW**: Use a multimeter to measure the resistance between the CAN HI and CAN LOW pins. The resulting resistance should be between 28k – 50k ohms.
4. **Measure resistance between CAN HI and GROUND**: Measure the resistance between CAN HI and ground. The result should be Mega ohms or open.
5. **Measure resistance between CAN LOW and GROUND**: Measure the resistance between CAN LOW and ground.

**Additional Resources**

If you’re new to CAN bus diagnostics, we recommend checking out these resources to help you troubleshoot CAN bus issues:

* **[Diagnosis Tips Automotive Academy](https://www.diagnosistips.com/automotiveacademy/can-bus)**: A comprehensive guide to CAN bus diagnosis.
* **[How to Test CAN BUS with a Multimeter](https://www.youtube.com/watch?v=JPE42HSJxAk)**: A video tutorial on testing CAN bus resistance with a multimeter.
* **[CAN BUS Troubleshooting Guide](https://copperhilltech.com/content/CAN-Troubleshooting-Guide.pdf)**: A detailed PDF guide on troubleshooting CAN bus issues.
* **[How to Test if Your CAN Termination Works Correctly](https://www.kvaser.com/developer-blog/how-to-test-your-can-termination-works-correctly)**: A step-by-step guide on testing CAN termination.

By following these steps and resources, you’ll be able to check CAN bus resistance and troubleshoot common CAN bus issues. Remember to always follow proper safety precautions when working with electrical systems.