General Motors OBD-II Trouble Codes

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General Motors OBD-II Trouble Codes – Owning a General Motors (GM) vehicle comes with the advantage of having access to the On-Board Diagnostics II (OBD-II) system. This system plays a crucial role in identifying and diagnosing potential issues in your vehicle. By reading and interpreting OBD-II trouble codes, you can gain insights into problems affecting your GM vehicle’s performance. In this article, we will explore the world of General Motors OBD-II trouble codes, understand their significance, and learn how to troubleshoot and fix them effectively.

General Motors OBD-II Trouble Codes List

The OBD-II DTC codes here generally apply to all OBD-II GM vehicles from 1996 and newer: GMC, Chevrolet, Buick, Cadillac, and former brands Oldsmobile, Pontiac, and Saturn. There may be slight changes depending on the year/model of vehicle, you would need to consult a factory service manual for specifics.

GM cars and light trucks use SAE J1850 VPW (Variable Pulse Width Modulation). There are some variations among imports such as the Cadillac Catera, which is a German Opel derivative, the Catera uses the European ISO 9141 protocol.

Troubleshooting and Fixing OBD-II Trouble Codes

When faced with OBD-II trouble codes, it’s essential to follow a systematic approach to troubleshoot and fix the underlying issues. Here are some steps to consider:

  1. Diagnosing the underlying cause of trouble codes

    Troubleshooting begins by examining the specific trouble code and understanding its implications. You can use online resources, repair manuals, or seek guidance from experienced technicians to gain insights into the potential causes related to the code.

  2. Common causes and potential solutions for specific trouble codes

    Each trouble code may have multiple potential causes. By analyzing the symptoms, conducting tests, and performing visual inspections, you can narrow down the possibilities. Common causes include faulty sensors, wiring issues, vacuum leaks, or failing components. Once the root cause is identified, appropriate repairs or replacements can be made.

  3. Importance of regular maintenance and addressing issues promptly

    Regular vehicle maintenance plays a crucial role in preventing OBD-II trouble codes. It includes tasks like oil changes, filter replacements, and spark plug inspections. Timely addressing any warning signs, such as unusual noises or poor performance, can help prevent more significant issues that trigger trouble codes.

  4. Seeking professional help when needed

    While DIY troubleshooting is possible for certain trouble codes, complex or hard-to-diagnose issues may require professional expertise. Skilled technicians have the knowledge, experience, and specialized equipment to diagnose and fix intricate problems. If you’re uncertain or unable to resolve the issue on your own, don’t hesitate to seek professional help.

Preventive Measures and Maintenance Tips

To minimize the occurrence of OBD-II trouble codes in your General Motors vehicle, consider the following preventive measures and maintenance tips:

  1. Importance of regular vehicle maintenance

    Adhering to the manufacturer’s recommended maintenance schedule is crucial. Regular servicing ensures that components and systems are in optimal condition, reducing the likelihood of trouble codes.

  2. Checking and replacing faulty sensors and components

    Faulty sensors, such as oxygen sensors or mass airflow sensors, can lead to trouble codes. Regularly inspecting these sensors and replacing them as needed helps maintain accurate readings and prevent issues.

  3. Monitoring vehicle performance and addressing issues proactively

    Pay attention to any changes in your vehicle’s performance, such as decreased fuel efficiency or rough idling. Addressing these issues promptly can prevent further damage and the triggering of trouble codes.


Understanding OBD-II trouble codes is essential for General Motors vehicle owners to effectively diagnose and resolve issues. By investing in an OBD-II scan tool and familiarizing yourself with common trouble codes, you can take proactive measures to maintain your vehicle’s performance and address problems promptly. Remember to prioritize regular maintenance, seek professional assistance when needed, and stay proactive in resolving issues to keep your General Motors vehicle running smoothly.


  1. What is the difference between OBD-I and OBD-II?

    OBD-I (On-Board Diagnostics I) was an earlier system that varied among car manufacturers, making diagnostics more challenging. OBD-II is a standardized system introduced in the mid-1990s, making it easier to diagnose issues and access trouble codes across different vehicles.

  2. Can I use a generic OBD-II scan tool for my General Motors vehicle?

    Yes, generic OBD-II scan tools are compatible with General Motors vehicles. However, using manufacturer-specific scan tools may provide more in-depth diagnostics and access to additional features.

  3. Are OBD-II trouble codes the same for all car manufacturers?

    The format and basic meanings of OBD-II trouble codes are standardized. However, specific codes and their interpretations may vary slightly between car manufacturers.

  4. How often should I check for trouble codes in my vehicle?

    It’s a good practice to periodically check for trouble codes, even if your vehicle is running smoothly. Performing regular scans can help identify potential issues before they worsen.

  5. What should I do if I can’t fix the issue indicated by a trouble code?

    If you’re unable to resolve the issue indicated by a trouble code, it’s recommended to seek professional assistance. Experienced technicians can provide specialized diagnostics and perform necessary repairs or replacements.