Remote Starters - What is a Bypass Module, and Why Does My Car Need One?

I get a ton of questions about remote start systems. There’s a lot of false information floating around online, and even when you call a store you might feel like you’re not getting the full story. The goal of this article is to help you understand what a “bypass” (or more accurately, a security interface module) is and why your car needs one.

What is a bypass module, and why does my car need one

In modern vehicles a key isn’t just a key anymore. Have you ever had a replacement made and noticed it doesn’t cost a couple of bucks like it used to? The number one reason for that is because the majority of modern vehicles use transponder chips inside the keys that tell the vehicle it’s authorized to start. Some manufacturers, like Honda and Toyota, call this an immobilizer.

Transponder chip? How does that work

A transponder chip is an electronic component inside your key. When you insert your key into the ignition (or in push-to-start vehicles, press the start button), an antenna near the key cylinder or button picks up the chip’s signal and sends that code to your vehicle’s computer.

If the code is correct, your vehicle will start and stay running. If the computer doesn’t recognize the code, the vehicle either won’t start or will shut off within a second or two.

It’s a simple but very effective system for preventing hotwiring and unauthorized starts.

What does this have to do with a bypass for remote start

A remote start system is essentially a fancy hotwire.

(Now don’t take that the wrong way — remote start systems are very secure and very safe!)

Because we need to “trick” the vehicle into starting and staying running remotely, the system has to present those same key codes at just the right time. Even if a remote start system is installed perfectly, the vehicle won’t start remotely if those codes aren’t provided, meaning it’ll stay cold in the winter.

That’s where the “bypass” or security interface module comes in. It takes care of sending those key codes for us with the proper programming, allowing your vehicle to start safely and securely.

Interface modules allow secure and safe remote starting

There are several trusted companies that make advanced interface modules capable of safely handling factory security systems. Brands like iDatalink, Firstech, Directed, Fortin, Eurostart, and Midcity Engineering have proven technology that integrates directly with your vehicle, not bypassing it.

These modules make it possible to start your car remotely as if it came from the factory that way, without compromising any of your existing security features.

Are there other methods or brands

Yes, there are other brands and methods that can get the job done. However, removing or defeating any factory-installed security feature to make a remote start work is risky and not recommended.

There are only a handful of vehicles on the road today that don’t have an interface module available. If yours happens to be one of them, make sure your installer clearly explains the risks involved before moving forward.

Important advice before you buy

All modern vehicles require an interface module, and most cars today have all their features covered by that module. Don’t let a shop upcharge you for things that are already included.

You can visit https://www.idatalink.com/ look up your vehicle, and see exactly what’s covered. The best shops understand this and sell a complete solution, not an add-on “bypass.”

If you see a price that seems suspiciously low, there’s probably a reason for it — often because the shop isn’t giving you the full story up front. PS - watch out for installation methods too - soldering or military splice are professional connections