Disconnecting your car battery is sometimes necessary for maintenance or repairs. However, in a 2006 Subaru WRX, like many modern vehicles, this action can lead to a loss of important settings and data stored in various control modules. This includes your radio presets, clock settings, and even engine management system parameters that optimize your car’s performance over time. Losing these settings can be inconvenient and may even cause your WRX to run less efficiently immediately after reconnecting the battery until it relearns.
One common misconception is that the accessory power outlets in a Subaru WRX remain powered even when the ignition is off, allowing for a simple 12V power source to maintain memory during a battery change. Unfortunately, this is not the case for the 2006 WRX and many other Subarus. These outlets are switched and do not provide constant power. So, how can you prevent memory loss when disconnecting your 2006 WRX battery? The answer lies in utilizing the OBD2 port.
The On-Board Diagnostics II (OBD2) port in your 2006 WRX, specifically pin 16, is designed to be always connected to the car’s electrical system. This constant power supply is intended for diagnostic tools and code readers, but it can also be cleverly used to maintain power to your car’s systems while the battery is disconnected.
Many professional service centers utilize specialized adapters that connect a 12V power source, such as a jump starter or battery maintainer, to the OBD2 port. This allows them to perform battery replacements or other electrical work without erasing your WRX’s learned settings. By feeding power through the OBD2 port and its associated 7.5 Amp fuse, you can effectively keep the car’s memory alive.
However, it’s crucial to understand the limitations and potential risks. The 7.5 Amp fuse protecting this circuit is designed for the minimal power draw of the car’s memory modules. If you inadvertently turn on any accessories while the battery is disconnected and power is supplied through the OBD2 port, you risk overloading this fuse. Even opening a door and activating the interior lights could draw enough current to blow the 7.5 Amp fuse.
If the fuse blows, you will unfortunately experience the same memory loss as if you had simply disconnected the battery without any power maintenance. Your radio presets and clock will reset, and the engine control module (ECM) might need to relearn its optimal settings, potentially causing a temporary rough idle.
While a blown 7.5 Amp fuse in this circuit will not trigger a check engine light (CEL), it will prevent a code reader that relies on vehicle power from operating correctly when plugged into the OBD2 port. This is because the power to the port itself will be interrupted by the blown fuse.
In conclusion, using the OBD2 port, specifically pin 16, can be a helpful technique to preserve your 2006 WRX’s memory when disconnecting the battery. However, it’s essential to proceed with caution and ensure that no accessories are turned on during the process to avoid blowing the 7.5 Amp fuse. Understanding this simple trick can save you the inconvenience of resetting your settings and allow for a smoother experience after battery maintenance on your 2006 Subaru WRX.
