Connecting your car’s On-Board Diagnostics (OBD2) system to a desktop or laptop computer with an RS232 port offers advanced diagnostics capabilities. This guide outlines the process using a Volvo as an example, highlighting key components and software.
While most modern vehicles utilize OBD2 standards, some older models, like the 1998 Volvo V90, require specific software and hardware. This guide will focus on using the VOL-FCR software and an RS232 interface cable for these specific vehicles.
Understanding the Connection Process
The connection requires an OBD2 to RS232 interface cable. This cable translates the signals from your car’s OBD2 port, located near the console, into signals understandable by your computer’s RS232 serial port. If your computer lacks an RS232 port, a readily available USB to RS232 converter can bridge the gap.
Required Software: VOL-FCR
VOL-FCR software, designed for older Volvos, is essential for this process. You can purchase it from Ilexa. This software is compatible with Windows XP and potentially later versions. It supports various Volvo models, including:
- 800 Series (’96)
- C70 (’97-’98)
- S/V40 (’97-’98)
- S/V70 (’97-’98)
- 900 (’96)
- S/V90
Connecting to Your Vehicle
- Connect the Interface: Plug the OBD2 end of the interface cable into your car’s OBD2 port. Connect the other end to your computer’s RS232 port or to a USB to RS232 converter plugged into a USB port.
- Launch VOL-FCR: Start the VOL-FCR software on your computer.
- Select Your Car Model: Choose your specific Volvo model from the list provided in the software. For a 1998 V90, select S/V90.
This setup allows access to various control units, including engine (Motronic 4.4), gearbox (AW30-49/3), Immobilizer 2, SRS, and RTI.
Accessing ABS and Cruise Control
VOL-FCR provides limited functionality for ABS and Cruise Control systems in these older models. While buttons for these systems exist within the software, using them requires constructing a separate flash code reader using a resistor, LED, and a push button switch, connecting to pins 12 and 13 on the OBD2 socket. The software provides instructions for this process, but proceed with caution as it carries inherent risks.
Remember to run the car and keep the ignition on before attempting to access ABS data using the flash code reader to allow the system to perform self-checks. Skipping this step can result in error codes.
Conclusion
Using a desktop or laptop with an RS232 connection to diagnose older Volvo vehicles via OBD2 requires specialized software and hardware like the VOL-FCR software and an OBD2 to RS232 interface cable. While the process can be complex, especially for ABS and Cruise Control systems, it offers valuable diagnostic insights for these specific vehicles. Remember to consult the VOL-FCR software documentation for detailed instructions and safety precautions.
