You stay responsible.
Watch the road. Be ready to steer and brake. Driver assistance can make mistakes.
New to comma?
Comma AI for Dummies · Beginner guide
What is comma 4? Start here.
A small device on your windshield that helps steer compatible cars. Learn what it does, check your car, and see what you need.
A quick answer before you dive in.
comma adds driver assistance to specific supported cars. It does not turn your car into a self-driving car.
Your car sets the limits.
Steering, speed control, required parts, and supported years vary by configuration.
Start with the basics.
Understand standard openpilot before choosing optional hardware or community software.
Four steps. In the right order.
Understand what you are buying.
comma four is the hardware. openpilot is the driver-assistance software. It can help with steering and speed on supported cars, with limits.
Check your exact car.
Match the model, year, and required equipment. A similar name or a different year is not a match.
Build the right shopping list.
You need the device and the right connection kit for your car. Check for any extra parts before paying.
Set up while parked.
Follow the official mounting and car connection instructions. Then install the software and learn how to take over before driving.
What you need to buy
- comma 4. The screen, its connecting cable, and two windshield mounts.
- Your car’s connection kit. Choose the kit for your exact car in comma’s shop. This is called a car harness.
- Any extra parts your car needs. Your car’s page lists the required parts.
Listed starting price: $999 USD. Select your car to confirm the total, including any extra parts, shipping and taxes.
Shop checked September 16, 2026. No paid subscription is required for the basic setup.
Questions
Do I need to know how to code?
The standard setup uses guided device installation. You still need to follow the instructions for your exact car, hardware, and software.
What is a harness?
A harness is the car-specific cable assembly used to connect the device. Choose the one listed for your exact car configuration.
What is a fork?
A fork is a community version of openpilot with its own features, support, and installation instructions. It is a separate software choice.
Can I copy someone else’s setup?
Only after checking that the exact car, year, equipment, device, and software match. A video is not a compatibility check.
A good start comes with the right fit.
Check the exact car requirements first. Then see the current comma four offer and the correct harness at comma.ai.
Referral disclosure: eligible new customers get $50 off. CommaGuide gets $50 after a qualifying purchase. Terms apply.
Related guides
Was this guide helpful?