Losing your car’s radio presets, clock settings, and seat positions after a battery change can be frustrating. An Obdii Settings Saver provides continuous power to the vehicle’s computer, preventing memory loss during battery disconnection. While commercial options are available, this guide demonstrates how to build a simple, reliable OBDII settings saver using readily available components.
Building Your Own OBDII Memory Saver
This DIY project offers a cost-effective solution for preserving vehicle settings during battery replacement. With basic soldering skills and a few parts, you can create a dependable memory saver in about an hour.
Parts List:
- 12V DC 2A mains powered regulated power supply
- 16-pin OBDII empty male plug with shell for cable entry (or an old OBDII clone dongle)
- Two 470 ohm 1/8w resistors (for LEDs)
- One 3mm green LED
- One 3mm red LED
- One 3A diode (e.g., 1N540)
Assembly:
The provided image illustrates the connections. Solder the diode’s cathode (negative side, marked with a band) to the positive wire of the power supply. Connect the diode’s anode (positive side) to pin 16 of the OBDII plug. Connect the resistors in series with their respective LEDs (longer positive lead to resistor). Connect both resistor/LED assemblies to the negative wire of the power supply. The red LED indicates power to the OBDII port, while the green LED confirms power from the external supply. Hardwiring the power supply connection is recommended for reliability.
Why Use an OBDII Memory Saver?
Modern vehicles rely on continuous power to maintain various settings, including:
- Radio presets
- Clock and date settings
- Seat and mirror positions
- Power window and sunroof settings
- Electronic control unit (ECU) configurations
Disconnecting the battery interrupts this power supply, potentially erasing stored data. An OBDII settings saver maintains power to these systems, preventing data loss and the need for reprogramming. This method utilizes the vehicle’s OBDII port, which typically has a permanent 12V power source, ensuring continuous power supply even with the ignition off.
Using Your OBDII Memory Saver: A Step-by-Step Guide
- Prepare the Vehicle: Turn off all accessories, including lights, radio, and climate control.
- Connect the Saver: Plug the memory saver into the OBDII diagnostic port under the dashboard. Only the red LED should illuminate, indicating connection to the car’s battery.
- Power Down: Turn off the ignition, close all doors and windows, and avoid using the remote locking key fob. This allows the vehicle’s systems to enter sleep mode. Wait approximately 5 minutes.
- Activate Power Supply: Plug the memory saver’s power supply into a mains outlet. Both red and green LEDs should now light up, confirming power to the vehicle.
- Replace the Battery: Disconnect the negative battery terminal first, followed by the positive terminal. Avoid touching the terminals together. Install the new battery, connecting the positive terminal first, then the negative.
- Disconnect the Saver: Unplug the memory saver’s power supply from the mains outlet and then remove the saver from the OBDII port.
- Verify Success: Turn on the ignition. If warning lights related to steering or other systems do not remain illuminated, the memory settings have been successfully preserved.
This simple DIY OBDII settings saver offers a practical and reliable solution for preventing memory loss during battery changes, saving you time and potential frustration. While this design lacks a fuse, it relies on the 2A power supply’s internal protection. However, exercising caution and avoiding shorts is crucial. Alternative power sources, like a second car battery or cigar lighter socket, are possible but less reliable due to potential voltage fluctuations or intermittent connections. Using a dedicated mains-powered supply, as described here, offers the most consistent and reliable power source for preserving your vehicle’s settings.
