Connecting a laptop to a car’s OBDI system to tune performance can be tricky. One common issue involves using an FTDI RS232 OBDII cable with TunerPro software. This article discusses troubleshooting steps and considerations when purchasing an FTDI-based cable.
Common Problems with FTDI RS232 OBDII Cables and TunerPro
A user reported issues connecting to their car’s OBDI system using an ALDL/RS232 cable with a serial-to-USB adapter and TunerPro software. Despite confirming power to the cable and the computer recognizing the adapter, TunerPro consistently displayed a “cable not found or not functioning” error. This error persisted even when the cable wasn’t connected to the car, suggesting a communication problem.
The user experimented with different COM port settings and baud rates within TunerPro and the device manager, including unchecking the “use 16550 compatible UART” option. They also noted a solid LED on the USB adapter when the ALDL cable was powered, questioning its significance. While the ALDL cable successfully initiated diagnostic mode on the car, indicating functionality, the connection with TunerPro remained problematic.
Understanding FTDI Chips and Serial-to-USB Adapters
The user mentioned a conversation with a technician who claimed only three types of serial-to-USB chips exist, regardless of the cable brand. This highlights the importance of the FTDI chip inside the adapter. While many cables might look similar, the quality and compatibility of the FTDI chip can significantly impact performance. The user considered purchasing an FTDI CHIPI-X10 due to its lower cost compared to complete ALDL to USB cables.
Choosing the Right FTDI RS232 OBDII Cable
When buying an FTDI RS232 OBDII cable, ensure it’s specifically designed for your vehicle’s make and model. Compatibility is crucial for proper communication. Consider these factors:
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Genuine FTDI Chip: Opt for cables with genuine FTDI chips. They generally offer better reliability and driver support. Counterfeit chips can lead to connection instability and communication errors.
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Driver Installation: Ensure the cable comes with or links to the correct drivers for your operating system. Proper driver installation is essential for the computer to recognize and communicate with the cable.
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Baud Rate Compatibility: Confirm the cable supports the required baud rate for your OBDI system and software. While 9600 baud is common, some systems may require different speeds.
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Quality Construction: A well-built cable with durable connectors and shielding can prevent signal interference and ensure a reliable connection.
Troubleshooting Tips for OBDII Cable Connection Issues
If you encounter connection problems, try these steps:
- Verify Power and Ground: Double-check the power and ground connections to the ALDL connector. Use a multimeter to confirm voltage.
- Check COM Port Settings: Ensure the COM port selected in TunerPro matches the port assigned to the cable in the device manager.
- Update Drivers: Install the latest drivers for your FTDI chip from the FTDI website. Outdated drivers can cause compatibility issues.
- Test with Different Software: Try using a different OBDII software to rule out TunerPro-specific problems.
Conclusion
Purchasing the right FTDI RS232 OBDII cable is crucial for successful vehicle diagnostics and tuning. By understanding the importance of genuine FTDI chips, driver compatibility, and baud rates, you can avoid common connection issues. If problems persist, systematic troubleshooting steps can help pinpoint the cause and ensure a reliable connection with TunerPro or other diagnostic software. Remember to always consult your vehicle and software documentation for specific requirements and recommendations.
