How to Start a Car Using OBD Port?

The onboard diagnostics (OBD) port in your car provides access to important information about your vehicle’s health and performance. With the right adapter, you can also use the OBD port to start your car remotely in a pinch. This can be a handy trick to know if you ever find yourself locked out of your running car or have a dead key fob battery.

In this comprehensive guide, we’ll cover everything you need to know about how to start a car using OBD port. Let’s get started!

What is the OBD Port and How Does It Work?

What is the OBD Port and How Does It Work?

The OBD port, also known as the OBD-II port, is a special connector found near the driver’s seat of most modern cars made after 1996. It provides access to the vehicle’s computer, called the engine control unit (ECU).

The ECU is essentially the car’s “brain” – it controls various systems and monitors sensor data like ignition timing, fuel injection, and emissions. It powers essential functions, like starting the engine. The OBD port allows you to “talk” to the ECU for important vehicle diagnostics. Mechanics use it to identify issues and extract error codes when the “Check Engine” light comes on.

In addition to diagnostics, the OBD port has another useful feature – it can send signals to start the engine remotely. This is possible due to the introduction of “smart keys” and keyless ignition systems in modern cars. With the right adapter connected to the OBD port, you can essentially mimic the signal from your key fob to start the car.

Why Use the OBD Port to Start Your Car?

There are a few useful scenarios where using the OBD port to start your car can come in handy:

If You’re Locked Out of the Car While It’s Running

We’ve all experienced this frustrating situation – you stop to pump gas, the car is running to keep the AC on, and you accidentally lock yourself out. Instead of waiting for a locksmith or dealing with the hassle of a spare key, you can quickly plug an adapter into the OBD port and start the car to unlock it.

For a Dead Key Fob Battery

Modern key fobs are convenient, but the battery dying at the wrong time can spell disaster. If the battery in your fob is dead, you may be completely stranded unless you have a physical key. Using the OBD adapter allows you to get in and on your way until you can replace the battery.

To Test and Diagnose Issues

Mechanics often use OBD adapters for troubleshooting if a car won’t start. If you can power the vehicle on via the OBD port, it tells you the issue likely isn’t related to the ECU or ignition system, but rather something like the battery or starter.

To Charge the Battery

In some cases, using the OBD adapter to start the car is enough to slightly recharge the battery if it’s too weak to turn the engine over on its own. This can be a handy last-ditch effort to revive the battery before calling for a jump start.

What Tools You’ll Need

Using the OBD port to start your car requires two key components:

OBD Adapter

This is a device that plugs into your car’s OBD port and allows communication with the ECU. There are many types of OBD adapters available:

  • Bluetooth adapters – These wirelessly connect to an app on your smartphone. Most apps allow you to view diagnostics, and error codes, and perform functions like remote start.
  • Dedicated remote start adapters – These are specifically designed with buttons to remote start/stop the engine. No app is required, just push a button on the adapter.
  • Multi-function scan tools – More advanced OBD2 scanner tools not only read error codes but allow configurations for remote start, key reprogramming, and other neat tricks.

I recommend a dedicated remote start adapter or a simple Bluetooth OBD connector that works with a remote start app. They are affordable, straightforward to use, and get the job done.

Smartphone App

If you opt for a Bluetooth adapter, you’ll also need a compatible app like OBD Fusion or OBD Auto Doctor. These apps connect to your OBD2 Bluetooth adapter and make the remote engine start possible from your smartphone. Most paid versions of OBD apps have the remote start function.

How to Locate the OBD Port in Your Car

OBD ports are usually located on or near the driver’s side footwell. They are often found under the dashboard, around the area your knees would be near the steering column.

Though the general location tends to be similar in most cars, the exact placement can vary. Here are some of the common OBD port locations to check in your car model:

  • Under the steering column near the hood release lever
  • Inside the driver’s side footwell near the hood release
  • Behind trim panels around the steering wheel
  • Behind ashtrays or coin trays in the console area
  • Driver’s side area near the parking brake
  • Behind or above fuse boxes near the accelerator pedal

If you’re having trouble finding it, your owner’s manual should provide the exact location. You can also Google image search “OBD port location” along with your car make and model to see visual examples.

Step-by-Step Instructions to Start Your Car

Step-by-Step Instructions to Start Your Car

Once you have your OBD adapter and have located the port, follow these steps to safely start your car:

1. Insert the Key

First, ensure your physical key is in the ignition. The car may not start remotely without the key for anti-theft reasons. Insert it but don’t turn it or start the engine.

2. Connect the OBD Adapter

Plug your Bluetooth OBD adapter or remote start fob adapter into the port. It only fits one way – don’t force it. Some adapters have an LED that lights up when properly connected.

3. Launch the App (Bluetooth Only)

For Bluetooth OBD connectors, launch your OBD app on your smartphone and connect to the adapter. Navigate to the section of the app with the “Start Engine” option.

4. Put Car in Neutral

Make sure the gear selector is in “Neutral” or “Park” as you normally would to start driving.

5. Press Start

  • For Bluetooth apps, tap the “Start Engine” button on your phone screen.
  • For dedicated remote start fob adapters, press the button on the adapter.

This sends the signal to the ECU to enable the ignition and turn over the starter, starting the engine.

6. Disconnect and Drive

Once running, disconnect the OBD adapter and safely store it before driving off. Take care not to lose small Bluetooth adapters in the footwell.

And that’s it – you’ve successfully fired up your car using just the OBD port!

Tips and Precautions

While using the OBD port to start your car is safe and straightforward when done properly, follow these tips and precautions:

  • Only use reputable OBD adapters to avoid damage to the ECU or electrical systems. Cheap knockoffs may have compatibility issues.
  • Never try this with a manual transmission car in gear or one that isn’t parked safely. The car could lurch forward unexpectedly.
  • Don’t crank the engine for more than 10 seconds continuously to avoid overheating the starter.
  • Make sure your battery has sufficient charge and the engine isn’t immobilized for anti-theft reasons. The remote start may fail or drain the battery further.
  • Disconnect the adapter before driving for safety and to prevent data leaks or ECU disruption in motion.
  • Only use this method as an emergency workaround, not a daily crutch to avoid using keys. Relying on it too much isn’t good practice.
  • Never remove or modify the OBD port connections in any way. This could lead to electrical faults or drivability issues.
  • Be aware that remote starting via OBD may disable autostart/stop fuel-saving features on some vehicle models.

Using common sense and following the proper steps, OBD remote start can be a safe DIY fix. Frequent issues may indicate underlying problems needing professional diagnosis.

Frequently Asked Questions

Does this work on all cars?

Most gasoline engine cars made after 1996 are OBD-II compliant and support remote starting through the port. Older or specialty models may not. Diesel and hybrid vehicles often don’t support remote start functions for safety reasons. Always check your owner’s manual to confirm if OBD remote start is possible and recommended.

Is this safe for my vehicle?

Using a reputable OBD adapter and app as intended is safe and shouldn’t cause any issues. However, cheap or faulty adapters that send incorrect signals can potentially disrupt the ECU. Only use quality, trusted adapters from reputable brands. Avoid excessively long or frequent remote starts, which could cause undue battery drain or wear on the starter motor.

Will this void my car warranty?

Using the OBD port capabilities shouldn’t void your factory warranty, as you’re not modifying anything, just accessing standard functions. However, always check your warranty terms to be 100% sure. Most automakers cover their mobile apps and OBD devices. But third-party add-ons may be a gray area if they cause an unlikely ECU issue down the road.

Can thieves use this to steal my car?

Possibly, but it’s not very likely. They would need specialized and relatively expensive scan tools. The more imminent concern is burglars using OBD key cloning devices to gain entry and steal belongings. So deter theft by keeping your OBD port covered and your car parked in well-lit areas. Never leave valuables visible inside.

Does this work on hybrid or electric cars?

Unfortunately no, most hybrids and EVs don’t support remote start through the OBD port. This is because there is no traditional “engine” to start and their high-voltage systems have unique complexities. Newer models are starting to offer OEM phone app remote control, but aftermarket OBD adapters remain incompatible. Check your hybrid’s features to confirm.

Will this work if my check engine light is on?

It depends on the nature of the underlying issue causing the check engine light. Minor faults may not prevent OBD remote start. However major engine management faults can disable the start function as a safety precaution. Diagnose and repair the issue first before relying on OBD remote start capabilities. The engine light could indicate serious problems.

Can I add an OBD remote start to an older car?

Adding full OBD-II remote start to pre-1996 vehicles isn’t straightforward. However, some older models without chip keys can be modified to accept very basic aftermarket remote starters wired directly into the ignition system. This is an involved expert-level project requiring altering ignition components. Consult a professional first to see if retrofitting a basic remote start is possible on your classic car.


The OBD port provides accessible engine management control as well as valuable vehicle diagnostics. With an appropriate adapter and app, it offers remote start capabilities on most modern vehicles. This can get you out of a jam if faced with a dead key fob or other issues. It’s also useful for troubleshooting problems that prevent starting. While not a full substitute for a proper remote car starter installation, OBD remote start is a neat, convenient function that requires minimal tools. The Essential Guide to Marine Engine Room Parts not only provides comprehensive insights into the intricate components of maritime propulsion systems but also emphasizes the importance of just using proper care and caution, treating it as a valuable resource to be relied upon occasionally, much like a backup when needed. With the steps and tips covered in this guide, you’ll not only master marine engine room essentials but also gain the knowledge to successfully start your car via the OBD port in various situat

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