How Ghost Gauges Work

Ghost Gauges connect directly to your vehicle through a compatible Bluetooth ELM327 adapter plugged into the OBD2 port. The gauge communicates with the vehicle’s ECU, requests live information and displays it on the selected screen in real time.

The ELM327 connection is completely wireless, so no data wires need to be run from the gauge to the OBD2 port. After the initial setup, the gauge remembers the adapter and automatically reconnects whenever the vehicle is started. A phone, mobile app or internet connection is not required during normal use.

Using Multiple Gauges

You only need one ELM327 adapter, even when using two or three displays. The gauges are linked together using the connections shown in the supplied wiring diagrams, allowing them to share the same vehicle data.

When Round Gauge 2 is installed, it normally manages the ELM327 connection and sends information to the other linked displays. If it is not installed, another compatible gauge can take over automatically. Each display can then be configured individually while remaining part of the same system.

This keeps the installation simple and prevents multiple gauges from competing for the same Bluetooth connection.

Assembly and Setup

Ghost Gauges are designed to be straightforward to assemble when using the recommended parts. Connect the ESP32, display, controls and linked gauges using the supplied diagrams. Then open the included flasher, select the gauge and display size you are building, and upload the correct software.

Once installed, plug the ELM327 adapter into the vehicle, switch on the ignition and allow the gauge to connect. The initial connection may take slightly longer while the gauge identifies the adapter. Future connections should be considerably faster because the connection type and adapter information are remembered.

Only 1 Cable needs to be connected to your car and thats power, you can use USBC to power the esp32 (the most common and easy way) or you can use a 12-5v buck converter and wire into a igniton switched fuze, either way is explained in the instructions manual

The settings and screens are controlled directly from the gauge, so a computer is only needed when initially installing or updating the software.

Vehicle Compatibility

Ghost Gauges are designed to work with most OBD2-compatible petrol and diesel vehicles. They support a wide range of Bluetooth Classic and Bluetooth Low Energy ELM327 adapters, including many Vgate, Konnwei and compatible aftermarket models.

However, the information available depends on the vehicle—not only the gauge. Different manufacturers, engines and ECUs expose different parameters. Common OBD2 information is widely supported, but some readings may be unavailable or may require manufacturer-specific communication. If the ECU does not provide a particular value, the gauge cannot create or accurately estimate that data.

For the most reliable installation, always use the exact ESP32 boards, screens and other components listed on our website. Parts that appear identical can use different controllers, pin layouts or internal hardware, so compatibility with unapproved alternatives cannot be guaranteed.

Common Questions

Do I need a phone or an app?
No. The gauge connects directly to the ELM327 adapter and operates independently.

Is an internet connection required?
No. All communication happens locally between the vehicle, adapter and gauges.

Do multiple gauges require multiple ELM327 adapters?
No. One gauge manages the vehicle connection and shares the data with the linked displays.

Will it reconnect automatically?
Yes. Once the adapter has been detected successfully, its connection information is saved for faster reconnection.

Will every parameter work on my vehicle?
Only parameters supplied by the vehicle’s ECU can be displayed. Support can vary between models, engines and production years.

Can I use any ESP32, display or ELM327 adapter?
Some alternatives may work, but similarly named parts are not always internally identical. We strongly recommend using the exact components listed on our website.

Is it difficult to build?
The system is designed for DIY assembly. If you carefully follow the supplied wiring diagrams and select the correct options in the flasher, the process is simple and does not require programming knowledge.