Drivers Education

How to Start a Car Without a Key Fob

This article reveals how to start a car without a key fob. Sometimes, your key fob could go bad or dead, meaning you take an alternative route, especially during emergencies.

If the car you must start without a key fob is a used car, make sure to check your fob for an emergency key. You may have failed to check it when buying the car, which is not plausible. Checking earlier, especially for a used car, reveals whether the emergency key is intact.

To start a car without a key fob, there’s always a backup system placed by several car manufacturers around the car steering. Turn the “switch” which is a plastic cap covering the mechanical key slot of your car. Cars like Mazda have this on the right-hand side of their steering column.

But before this is possible, you may need to gain entrance into the car, once you gain entrance into the car, there are several ways to start a car without a key fob.

Can you drive a car without the key fob?

Yes, you can drive a car without the key fob once the engine is running. Moreover, you can shift to drive (D) from park (P) without the key in the car.

If the vehicle is a keyless vehicle, you must press the start button to run the engine. When your car detects and authenticates the fob, you may then start the engine.

In most electronic vehicles, you do not find an engine, and so nothing to start. Since the car depends on the key fob, you’d have to authenticate the key fob before you can put the car in reverse or drive.

Read also: sometimes engine revs but car won’t start: why?

You may also be able to control your car with an app. On a typical Tesla car, your phone can unlock the vehicle, so you do not need the car fob to put a Tesla in the drive. Make sure to have configured the PIN for enhanced security.

7 Ways to Start a Car Without a Key Fob

Most modern vehicles provide options to get your engine firing with no key fob. So, this section reveals how to start a car without a key fob:

  1. Use the Mobile App

Some automakers use the remote door unlock feature that lets you access a car when you’re locked outside, locked the car key inside, or have a disabled key fob.

A vehicle with no advanced remote unlocking system can seek road assistance to get inside the car. However, if you did not set up this functionality before losing your key fob, which requires a PIN set up, you might find it tougher to get inside your car.

  1. Hotwire to Bypass Ignition Lock

Hotwiring a car is when you bypass or get around the ignition lock/switch mechanism. It involves connecting a series of cables or wires to start the engine. The security of the vehicle is the ignition lock.

When a car key is a lock, it can turn a circular switch pack that connects the appropriate wire for a successful connection. To hotwire a car is mostly done by hand; it’s quite complicated and technical, and the reality is different than what you may have learned.

Meanwhile, since the ’93 in Europe and 90s in America, vehicles featured passive immobilizers installed with a reader near the ignition barrel. It typically searches for a signal coming from a chip inside the key fob. So, no chip means no signal, and the car won’t start.

If the operation involves stealing a car, for example, hotwiring is not the ideal method as it’d take several minutes, compared to movie scenes, to bypass and get the vehicle running. The reason is that the ECU shuts down or disables some components, including sparkplugs power, fuel pump power, and crank sensor power, because of lack of signal.

  1. ECU Replacement

Earlier systems could be beaten, though, especially if you conduct the two needed things well.

Firstly, you install a performance chip in the ECU system as Superchips. This installation will replace the primary ECU chip with another with enhanced raised rev limits and better fuelling maps. Unfortunately, the immobilizer system becomes inactive, and the vehicle has no security.

Read also: a good bulb but activating brake light

Secondly, you may visit a scrap yard and get the ECU and switch the reader, chip, and ECU from another car to the one you must start with keyless ignition. This practice typically takes longer, but it does not require panel beating to get it done. After replacement, break the ignition lock and get rid of the ignition switch. Now, hold the replacement chip by the reader and turn the ignition switch using a screwdriver to start the vehicle.

  1. Start the Car Directly

Once you get inside your car, starting the car becomes easier. Most car manufacturers know that there’d be a need for keyless ignition if the fob dies, and there’s a system that has been designed to function without a non-functioning remote. Most cars are equipped with a means of starting your car manually, while others have backups built into the key fob that works pretty well without a key.

start a car without a key fob
The “Switch” that covers the Key Hole

Somewhere around the steering column, there’s a key slot even if your car has a keyless entry which you may not have noticed. Cars like Mazda are equipped this way. Just turn the “switch”, which is actually a plastic cap that covers your key slot.

use a key to start a car without a key fob


  1. Push Start

You can push-start your automatic car, for instance, to fire the engine. However, your battery must have a bit of charge to enable the dash, even if it’s not enough for the starter.

You would simply push the ignition button twice without matching the brake, push the vehicle, and pop into gear.

If the battery is dead, you may not be able to start the vehicle, except you push button override. You would find this feature in some brands like Mercedes in case you have a dead key fob battery.

Alternative: Change the Key Fob Battery

The best practice is to change your key fob battery to get it to function. You may open the fob to access the battery using a small screwdriver.

The key fob battery is similar to a silver button. When getting a replacement key fob battery, make sure to match the battery numbers.


Can I use my phone as a key fob?

Depending on your manufacturer, yes, you may be able to use your phone app as a key fob. Typically, however, key fobs are not designed with NFC but using RFID technology. So, it may not be possible to copy or replicate your key to a mobile phone with application software. Instead, copy the key fob to a sticker, such that when you place the sticker on a mobile phone, it can function as a key fob.

Will, any key fob work for any car?

Yes, any key fob will work for any car, but you must reprogram the key fob to the other car if the key is the same.

Final Thoughts

To crank a vehicle engine, the ignition switch with a key must complete the electrical circuit. If you are following a method like hotwiring, movie scenes, simply show the character cutting the cables to bypass the switch, allowing the vehicle to start. Although possible, it is not safe.

The best thing to keep a spare fob, typically in your center console. Remove the battery when storing it, though.

Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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