Remote start and key questions, answered over the fence

Neighbors ask

The short answer first

Yes, remote start and your car key are connected, but they are not the same thing. The key (or the chip inside it) proves to the car that it is allowed to run. The remote start feature is a separate convenience that lets the engine run for a while without that proof being sitting in the ignition, because the car has been told to trust a signal from your fob or phone instead.

That is why people get confused when something goes wrong. If your remote start stops working, your regular key may still start the car just fine. If you lose your regular key, the remote might still unlock the doors but refuse to let the engine turn over. Two systems, two failure paths.

So when a neighbor asks us whether remote start means they need a special key, the honest answer is: it depends on whether the remote start came from the factory or was added later, and on what the car expects to see before it will fire up. The rest of this page walks through that, one piece at a time.

What your car is actually checking when it starts

Most vehicles built in the last couple of decades carry an immobilizer. Inside the plastic head of the key sits a tiny transponder chip, and when you turn the key (or press a start button with the fob nearby) the car sends out a low power signal that wakes the chip. The chip answers with a code, and only if the code matches what the car has stored will the fuel and ignition systems be allowed to work.

This is why a key that is cut perfectly can still turn in the ignition and do nothing. The metal blade matches the cylinder, but the chip has never been introduced to the car. Our page on what a transponder chip is goes deeper on how that handshake works.

Remote start has to deal with that same handshake. Without a key in the ignition, something has to answer the car's question. How that answer happens is the whole difference between a factory system and an add on one, and it is where most of the practical questions come from.

Push button cars add one more twist. There, the fob never goes into a slot at all, so the car has to find it by radio. Inside the cabin, a set of antennas listens for the fob, and the engine will only start if one is detected nearby. That is also why a remote started engine commonly stops once you open the door and the car cannot find a fob inside, a design choice that keeps a running car from being driven away by someone who has no key at all.

Factory remote start versus a system added later

A factory system was designed together with the car. The engine computer already knows the remote start command is legitimate, because it arrives from the same module that handles the fob. There is usually no extra wiring trick involved, and the car typically shuts the engine off the moment you press the brake pedal or open a door unless the real key is present.

An aftermarket system is a box installed by a shop, often tucked under the dash, that has to persuade the car to run without the real key. Many of them do this with a bypass module that stores a copy of the immobilizer information, or with a spare key sealed inside the dash. If that sounds like a lot of moving parts, it is, which is why the quality of the installation matters so much.

From a locksmith's seat, the main thing we ask is simply: which kind do you have? If you are not sure, the paperwork from the install, or a second fob that looks different from your factory one, usually settles it. Either way, the original key and the remote start hardware need to be treated as a pair when you plan any key work.

Why the lock button and the engine are separate stories

The buttons on a fob that lock, unlock and pop the trunk talk to the car through a radio signal. That signal has nothing to do with whether the engine will start. A fob can be perfectly good at unlocking doors and still contain a dead or unprogrammed chip, or a worn battery that is too weak for the start button to work reliably.

Likewise, you can lose the remote function entirely, with every button dead, and still start the car by placing the physical key (or fob) where the car expects it. Many push button cars have a spot, often in the center console or near the steering column, where a fob with a flat battery can be held so the car can read the chip by very short range coupling.

Knowing that split saves a lot of worry. If your buttons quit, you have not necessarily lost your ability to drive. If your car refuses to crank, the cause is not always the remote either. Our guide on what to do when a key fob stops working sorts out those symptoms in the order we would check them.

What happens when you lose the remote start fob

Losing a fob that has remote start is a bigger event than losing a plain key, simply because there is more to put back. The replacement has to be cut or matched to the vehicle, its chip has to be introduced to the car, its remote functions have to be paired, and in some setups the remote start piece has to be paired as well.

On many factory systems, a locksmith with the right equipment can program a new fob so that every function comes along. On some add on systems, the remote start has its own transmitter that is paired to the box under the dash, and replacing it can be a separate step that the original installer's brand of equipment controls. We will tell you honestly which situation your car looks like once we see it.

If you have lost every key to the car, that is a different but common situation, and it is handled with a programmed replacement rather than a copy. Our page on replacement car keys describes how that process runs from start to finish.

Spare keys, valet keys and the one in the drawer

It is worth knowing how many working keys your car has right now. Many households have a main fob, a spare in a kitchen drawer, and maybe an old plain key that opens the doors but cannot start the engine. That last one is often called a valet key, and it is deliberately limited so it can be handed to someone without giving them full control of the car.

If your vehicle has remote start, keep the fob that carries that feature somewhere you can reach it, and keep the spare somewhere separate. A neighbor of ours once described losing both in the same jacket pocket, which is a lesson in itself: two keys in one place is functionally one key.

When you plan for a spare, tell the person making it exactly which functions you want. A bare key that starts the car is one product. A full fob that also locks, unlocks and starts remotely is another. Our page on key programming and fobs explains what goes into each so you can decide what is worth having.

The lockout trap with a running engine

Here is a scenario worth picturing. You start the car from the kitchen window, walk out, climb in, then step back out to grab something you forgot, and the door clunks shut. Depending on the car and the system, the doors may lock themselves behind you with the engine still running and the key still inside.

Most modern cars have logic to prevent that, such as refusing to lock if the fob is detected inside, but not every vehicle behaves the same way and not every add on system includes the safeguard. It is a good habit to carry the fob in a pocket, not on the seat, any time you are near a car that might be running.

If you do end up locked out with the engine running, stay calm and keep yourself safe. Our page on getting back into a locked car explains what a professional does and what you can prepare. If a child or a pet is inside, call emergency services first, before anyone else.

Cold mornings and the mountain towns

Anyone who has scraped frost off a windshield in Mount Shasta, Dunsmuir or McCloud understands why people add remote start. Warming the cabin before you get in is a real comfort, and so is starting the car for a moment on a hot Redding afternoon so the air conditioning can begin to cool the seats.

Cold also quietly causes key trouble. Batteries in fobs lose strength in low temperatures, so a fob that works fine in July might become unreliable on a freezing morning. Frost can also stiffen a door lock or stick a handle, which is often mistaken for a key problem when it is really a weather problem.

If your remote start only fails on the coldest days, swap the fob battery before assuming anything bigger is wrong. If it fails no matter the weather, the transmitter, the receiver or the programming is a more likely culprit, and that is a good moment to ask a pro to look rather than keep guessing.

Buying a car that already has remote start

Used cars sometimes come with a remote start system the new owner never asked for, and the seller may or may not have passed along every transmitter. Before you sign anything, ask how many fobs exist, try each one, and confirm that the start button actually works on every one of them. Our note on the extra key question when buying a used car covers that conversation in more detail.

If the car has an add on system, there may be a hidden spare key or a bypass module somewhere behind the dash. You do not need to go looking for it, but it is fair to ask the seller or the installer where it lives, because that information matters if the car ever needs its keys reprogrammed or its computer replaced.

A few minutes of questions at the start can save a frustrating week later. Most people only discover how many keys they truly own on the day they need one, and by then the seller is long gone and the old paperwork is in a box nobody can find. Treat the key count as part of the price of the car, the same way you would treat the tires.

Simple checks before you call anyone

Start with the fob battery. Open the case, note which type is inside, and replace it with a fresh one of the same type, being careful to put it back the same way around. A surprising number of remote start complaints disappear at this step.

Then try the spare. If the spare works and the main fob does not, the problem is in the main fob. If neither works, the fault is more likely in the car or the remote start module. Also check whether the car is in a state that blocks remote start, such as a door, hood or trunk being open, or the brake pedal being pressed, because many systems refuse to run in those conditions on purpose.

Write down what you notice: which buttons work, which do not, whether the dash lights flash, whether the engine cranks and dies. Those details help a lot. They turn a vague complaint into a short list that a technician can use to point at one of the likely causes.

What to have ready when you ask a locksmith about it

Having a few facts nearby makes any conversation about keys smoother. Know the make, model and year, whether it uses a push button or a turn key, how many working keys exist, and whether the remote start is original or was added later. If you have any paperwork from an installation, set it aside.

Be ready to show proof that the vehicle is yours, since any responsible locksmith will want to confirm that before making or programming a key. This protects you as much as it protects the person who owns the car. Our guide on what to have ready when you call a locksmith has a fuller checklist.

When you are ready, you can describe the situation on our request form. Mention that the car has remote start, and say whether you still have any key at all. That one sentence tells us whether to plan for a simple fob job or a full programming visit, and it helps us bring the right equipment in the van.

Good to know

Common questions