Encountering a “non compliant” message when you plug in your car scanner can be frustrating, especially when dealing with a vehicle that’s supposed to be OBD2 compliant. Many car owners have faced this perplexing issue, particularly with older models that bridge the gap between older and newer diagnostic standards. This article dives into a real-world scenario with a 1999 Lexus GS300, exploring why your scanner might be giving you this error and what it actually means for diagnosing your vehicle.
Understanding OBD2 Compatibility
OBD2 (On-Board Diagnostics II) is a standardized system implemented in vehicles to monitor and report on various engine and emissions-related parameters. Introduced in the mid-1990s in the United States, OBD2 aimed to provide mechanics and vehicle owners with a universal way to access diagnostic information using a standard 16-pin connector and communication protocols. Ideally, any OBD2 scanner should be able to communicate with any OBD2 compliant vehicle, regardless of make or model.
However, the transition to OBD2 wasn’t always seamless, and the early years saw variations in implementation. While the 16-pin connector became standard, the underlying communication protocols could differ. This brings us to the curious case of the 1999 Lexus GS300.
The 1999 Lexus GS300 OBD2 Mystery
One Lexus GS300 owner reported a frustrating experience: despite having a 16-pin OBD2 connector, their aftermarket code reader failed to recognize the vehicle, displaying a “non compliant” message. This occurred even though the same scanner worked perfectly on other cars, including a Lexus IS200 of a similar era.
This raises a significant question: why would a 1999 Lexus GS300, equipped with a seemingly standard OBD2 port, refuse to communicate with a generic OBD2 scanner? The owner’s investigation led them to contact Lexus dealerships, but the responses were unhelpful, even suggesting a lack of familiarity with OBD2.
Seeking clarification, the owner contacted Lexus GB directly. The official response confirmed that the 1999 GS300 is indeed OBD2 compliant. This official confirmation deepens the mystery – if the car is OBD2 compliant, why the “non compliant” error?
Potential Reasons for Scanner Incompatibility
Several factors could explain why a car scanner might fail to communicate with a supposedly OBD2 compliant vehicle like the 1999 Lexus GS300:
- Protocol Variations: While OBD2 standardizes the connector and general diagnostic parameters, it allows for several communication protocols (like J1850 VPW, ISO 9141-2, CAN, etc.). It’s possible that the 1999 GS300 uses a protocol that is not universally supported by all aftermarket scanners, especially older or basic models. The owner in the original post suspected SAE J1850 VPW protocol based on pin connections, but even scanners supporting this protocol failed.
- Scanner Limitations: Not all OBD2 scanners are created equal. Budget-friendly or older scanners might have limited protocol coverage. They might work with common protocols but miss out on less prevalent ones or specific manufacturer implementations within the OBD2 framework. A more advanced or professional-grade scanner with broader protocol support might be necessary.
- Software Glitches or Scanner Bugs: Occasionally, the issue might lie with the scanner itself. Software bugs or glitches in the scanner’s firmware could lead to misidentification of the vehicle or communication errors.
- Wiring or Connector Issues: Although less likely if other cars work with the scanner, a fault in the GS300’s OBD2 port wiring or connector could prevent proper communication. However, the owner confirmed pin connections were present, making this less probable.
Resolving the “Non Compliant” Scanner Issue
If you encounter a “non compliant” message on your 1999 Lexus GS300 (or similar older vehicle), here’s a troubleshooting approach:
- Verify Scanner Protocol Support: Check your scanner’s specifications to see which OBD2 protocols it supports. Compare this to known protocols used by Lexus around that year if possible.
- Try a Different Scanner: Borrow or try a more advanced OBD2 scanner, preferably one known for broader vehicle compatibility or protocol coverage. A professional-grade scanner might be more successful.
- Check for OBD1 Bridging: In some transitional vehicles, manufacturers might have used a hybrid approach, incorporating some OBD1 elements within the OBD2 system. While the GS300 is officially OBD2, exploring this possibility (though less likely given Lexus’s confirmation) might offer insights.
- Consult a Professional: If you remain unable to connect, seek assistance from a qualified mechanic or a Lexus specialist. They will have access to professional-grade diagnostic tools and expertise to diagnose the communication issue effectively.
Conclusion
The “Car Scanner Says Non Compliant” message on a 1999 Lexus GS300 highlights the complexities that can arise even with standardized systems like OBD2. While the vehicle is officially OBD2 compliant, variations in protocol implementation and scanner limitations can lead to communication failures. By understanding these potential issues and following a systematic troubleshooting approach, you can better diagnose your vehicle and ensure you can access the valuable diagnostic information OBD2 is designed to provide. Sometimes, the issue isn’t non-compliance, but rather a matter of finding the right tool for the specific communication nuances of your vehicle.
