Are you experiencing trouble getting your ELM327 OBDII adapter to communicate with your Windows computer? Many DIY car enthusiasts and professional mechanics rely on ELM327 interfaces for vehicle diagnostics, but a common stumbling block is driver compatibility, particularly with the PL2303 USB-to-serial chip often found within these devices. If you’re facing a yellow error symbol in your Device Manager next to your COM port after plugging in your ELM327 adapter, you’re likely encountering the infamous PL2303 driver problem. This article will guide you through resolving this issue, ensuring your ELM327 adapter and PL2303 USB OBDII driver work seamlessly with your Windows system.
When you encounter this problem, Windows’ Device Manager often provides a cryptic “Code 10” error, indicating a “non-existent device has been specified.” This generic message doesn’t pinpoint the root cause, leaving users frustrated.
Initial troubleshooting steps, like downloading the latest PL2303 driver from Prolific’s website, often prove ineffective. Similarly, disabling and re-enabling devices in Device Manager yields no positive results. The core issue often stems from driver incompatibility, especially with older ELM327 adapters utilizing the PL2303HXA chip.
To understand the problem, it’s essential to identify the USB communication chip inside your ELM327 adapter. By carefully disassembling the device, you can typically locate the chip. If you find the inscription “PL-2303HX,” you’re dealing with a Prolific PL2303 chip. Visiting the Prolific website reveals crucial driver information: while they offer drivers for various PL2303 chip versions (HXA, XA, HXD, EA, RA, SA, TA, and TB), support for Windows 8, 8.1, and 10 is limited for older, end-of-life (EOL) PL-2303HXA and PL-2303X chips.
The crucial distinction lies between the PL-2303HX and PL-2303HXA. The chip itself usually contains a secondary code following “PL-2303HX,” such as “LFXXXXXA.” The last letter, in this case, ‘A’, signifies the PL-2303HXA revision – the very chip that lacks full support in recent driver versions for Windows 8 and later.
Checking the currently installed driver version in your system often reveals the latest driver (e.g., version 3.8.3.0, dated May-28-2017), which, despite being the most recent, may not be compatible with your older PL2303HXA based ELM327 adapter.
The solution lies in reverting to an older, compatible driver. A proven approach is to install a legacy driver version, specifically version 3.2.0.0, originally designed for Windows Vista. This older driver often provides the necessary support for the PL-2303HXA chip and can restore functionality to your ELM327 adapter. This driver version is available in both 32-bit and 64-bit flavors to suit different Windows system architectures.
Step-by-Step Guide: Installing the Legacy PL2303 Driver (Version 3.2.0.0)
Follow these steps to install the older PL2303 USB OBDII driver and resolve the compatibility issue:
-
Download the Driver: Obtain the PL2303 USB driver version 3.2.0.0 (for Vista 32 or 64 bit depending on your system). Save the driver package to an easily accessible location on your computer.
-
Disconnect ELM327 Adapter: If your ELM327 device is currently plugged in, disconnect it from the USB port.
-
Install the Driver: Locate the downloaded driver file and run the installer by double-clicking on it. Follow the on-screen instructions to complete the installation process.
-
Connect ELM327 Adapter: Once the driver installation is finished, connect your ELM327 adapter to a USB port. Windows will initiate the device detection process automatically. It’s possible Windows may display a “driver installation failed” message during this stage – this is normal and can be ignored.
-
Open Device Manager: Right-click on the Windows “Start” button and select “Device Manager.” Locate the COM port associated with your ELM327 adapter; it will likely still display the yellow error symbol.
-
Update Driver Manually: Double-click on the problematic COM port entry to open its “Properties” window. Navigate to the “Driver” tab and click on the “Update driver” button.
-
Browse My Computer for Drivers: In the “Update Drivers” window, choose the option “Browse my computer for drivers.”
-
Let Me Pick from a List: Next, select “Let me pick from a list of available drivers on my computer.” This option allows you to choose from previously installed drivers.
-
Select Version 3.2.0.0: From the list of drivers, you should now see the older driver version 3.2.0.0 that you just installed, alongside the newer, potentially problematic driver. Select the “version 3.2.0.0” driver and click “Next.”
-
Verify Driver Installation: After Windows installs the selected driver, check the device properties again in Device Manager. The yellow error symbol should be gone, and the driver version displayed in the “Driver” tab should now be 3.2.0.0. Your PL2303 USB OBDII driver should now be correctly installed and functioning.
Important Considerations
Remember that this driver adjustment might be necessary for each USB port you use with your ELM327 adapter. Windows typically installs the newest driver available whenever a device is connected to a new USB port. Therefore, if you switch USB ports, you may need to repeat steps 5 through 10 to ensure the older, compatible driver is used for that specific port as well.
While version 3.2.0.0 is a reliable solution, older driver versions might also work. These are often available online and could be helpful if you encounter issues with version 3.2.0.0. Having access to a range of legacy PL2303 USB OBDII drivers can be beneficial for troubleshooting various compatibility scenarios.
By following these steps, you can overcome the PL2303 USB OBDII driver challenge and get your ELM327 adapter working correctly, allowing you to proceed with your vehicle diagnostics and repairs without further driver-related headaches.
