Disconnecting your car battery is sometimes necessary for maintenance or repairs. However, for 2012 Subaru WRX owners, this can lead to an annoying issue: the loss of your radio presets, clock settings, and even engine management system (ECU) learned data. This article explores how to prevent this memory loss in your 2012 WRX using the OBD2 port.
Why Battery Disconnection Resets Settings in Your 2012 WRX?
Modern vehicles like the 2012 WRX rely on constant power to retain settings in various control modules. These modules “learn” and store data to optimize engine performance and other functions. When battery power is removed, these modules, along with your radio and clock, lose their power source and revert to default settings.
Utilizing the OBD2 Port on Your 2012 WRX to Preserve Memory
Fortunately, there’s a way to provide temporary power to your 2012 WRX’s electrical system while the battery is disconnected. The On-Board Diagnostics II (OBD2) connector, specifically pin 16, is constantly powered, even when the ignition is off. This provides a convenient access point to feed power into the system and keep those crucial settings intact.
Pin 16: Your Constant Power Source
Pin 16 of your 2012 WRX’s OBD2 port is designed to always be “hot,” meaning it receives power directly from the battery, bypassing the ignition switch. This is primarily for diagnostic purposes, allowing code readers to function even when the car is off. However, this constant power supply can be cleverly repurposed to maintain vehicle memory during battery changes.
Using a Memory Saver Device
Automotive service centers often utilize specialized “memory saver” devices. These tools typically consist of a 12V power source, such as a jump starter or battery pack, and an OBD2 connector. By plugging the memory saver into your 2012 WRX’s OBD2 port, you can supply power to the system through pin 16, effectively preventing memory loss when you disconnect the main battery.
Fuse Safety: The 7.5 Amp Limit
It’s crucial to understand the limitations when using the OBD2 port for this purpose. The circuit is typically protected by a 7.5 Amp fuse. This is sufficient to power the car’s modules and retain memory, which requires minimal amperage. However, if you accidentally turn on any accessories – even opening a door and activating the interior lights – you could easily exceed this 7.5 Amp limit. Drawing too much current will blow the fuse, defeating the purpose and potentially causing the very memory loss you were trying to avoid.
Precautions When Using the OBD2 Port for Memory Saving
When using the OBD2 port on your 2012 WRX as a power source during battery disconnection, remember these key precautions:
- Ensure all accessories are OFF: Radio, lights, climate control, everything.
- Avoid opening doors: Interior lights can draw significant current.
- Use a fused memory saver: This adds an extra layer of protection.
- Double-check polarity: Incorrect polarity can damage your vehicle’s electrical system.
Conclusion: A Simple Solution with Careful Execution
Using the OBD2 port on your 2012 WRX to maintain settings during battery disconnection is a smart technique. By utilizing pin 16 and a memory saver, you can avoid the inconvenience of reset radio stations and clock, and ensure your ECU retains its learned settings. However, caution is paramount. Always be mindful of the 7.5 Amp fuse limit and ensure all vehicle accessories are turned off to prevent blowing the fuse and inadvertently losing your settings. With careful execution, this method can save you time and frustration during battery maintenance on your 2012 WRX.
