You press the button and nothing happens. You press it again, harder, then hold the fob up beside your head because somebody once told you that extends the range. The car sits there. Behind that silence is either a fault worth about a dollar or a fault worth a few hundred, and standing in the car park pressing the button is the slowest possible way to find out which.
A dead fob is four different problems wearing the same face. The cell, the fob itself, the vehicle, or something in the air between them. Each one has a different bill attached and a different person who can fix it, and you can narrow it to one in about two minutes before you phone anybody.
Short version: Test in this order. The coin cell, then the spare fob, then the vehicle’s own battery, then the location. A fob that works indoors and fails in the cold is a weakening cell. A fob that fails everywhere while the spare works normally is a fob fault. Both fobs dead points at the vehicle. Since 1 September 2007 every new light vehicle sold in Canada has had to carry an immobilization system (Transport Canada news release, 6 September 2007), and the standard behind it requires a minimum of 50,000 code variants. That is why a fob is a coded device and not a spare key you can have cut while you wait.
Standing outside the car right now? Read what to do when you are locked out first, and how we check listings for what we check about a business before it appears on this site.
Four faults, one symptom
The reason a dead fob feels unfixable is that the symptom carries no information. Nothing happens, and nothing happening looks identical whether the cause costs a dollar or a day’s wages. The four causes do separate cleanly, though, and they separate on things you can observe without a tool.
| What you observe | Most likely cause | Who resolves it | What drives the bill |
|---|---|---|---|
| Works indoors, fails outside in the cold | Weakening coin cell | You, at a shop counter | The price of one cell |
| Fails everywhere, spare fob works normally | The fob | Auto locksmith or dealer | Replacement fob plus programming time |
| Both fobs dead, interior lights dim or absent | Vehicle battery or receiver | Garage, auto electrician or dealer | Diagnosis time before any part |
| Fails in one location only, fine elsewhere | Local radio interference | Move the vehicle and retest | Nothing, if you catch it |
Two of those four rows cost nothing to resolve. That is the whole argument for spending two minutes on the sequence rather than making the call first and finding out afterwards.
Start with the cell, because it is the cheapest thing to rule out
The coin cell inside the fob is the single most common failure and the only one you can settle for pocket change. The tell is range. A fob that opens the car from arm’s length but no longer from across the driveway, when it used to work from across the driveway, is running on a cell near the end of its life. Cold sharpens this: the same cell that manages one more press in a warm hand gives up in a car park in January.
Fit a fresh cell of the exact printed code before you conclude anything else. The code is stamped on the flat face of the cell already in the fob, and matching it by eye rather than by code is the usual mistake. We covered what that cell costs, where the published prices actually come from, and why the failure clusters in December in our guide to key fob battery replacement in Canada.
Then stop. If a fresh cell of the correct code does not bring the fob back, resist the urge to keep replacing parts. You have now ruled out the cheap cause, and everything after this point is somebody’s labour.
What the law turned your fob into
People expect a fob to behave like a key because it lives on the same ring as one. It does not, and the reason is regulatory rather than commercial. A Canadian light vehicle built for sale after September 2007 has to refuse to run for anything that cannot prove itself electronically.
| Requirement | Figure | Source and date |
|---|---|---|
| Immobilization system required on new vehicles under 4,536 kg GVWR | From 1 September 2007 | Transport Canada news release, 6 September 2007 |
| Minimum code variants the system must support | 50,000 | Canada Gazette, Part II, SOR/2011-69, Standard 114, 30 March 2011 |
| Time within which the system must arm after the disarming device is removed | 1 minute or less | Canada Gazette, Part II, SOR/2011-69, Standard 114, 30 March 2011 |
| Distance an immobilized vehicle may move under its own power | 3 m maximum | Canada Gazette, Part II, SOR/2011-69, Standard 114, 30 March 2011 |
| Motor vehicle thefts recorded by police, Canada, 2025 | 83,652 incidents, 201 per 100,000, down 16% | Statistics Canada, Police-reported crime statistics, released 22 July 2026 |
Read the second row again, because it explains most of the frustration in this topic. A system with a floor of 50,000 code variants cannot be duplicated by cutting metal. The fob has to be introduced to the vehicle by equipment that can talk to it, and that equipment is why a replacement is a booking rather than a purchase.
The third and fourth rows explain a different confusion. Standard 114 describes a system that arms itself quickly and then inhibits an electronic control unit so the vehicle will not move. A car that unlocks but will not start is not behaving strangely. It is doing exactly what the regulation describes, and the fault sits on the start side rather than the door side.
When the fault is the vehicle and not the fob
The check that settles this costs nothing and almost nobody does it. Try the spare fob. If the spare works normally, the vehicle is fine and the first fob is the problem. If both fobs behave the same way, the fob is almost certainly innocent.
Look at the vehicle’s own power next. Dim interior lights, a dashboard that takes a moment to wake, a clock that has reset itself: these point at the vehicle battery, and a vehicle battery low enough to affect the receiver will affect other things you can see. This matters because the two repairs go to different trades. A fob fault is auto locksmith or dealer work. A vehicle electrical fault is garage work, and paying a locksmith to diagnose it is paying the wrong person to look at the right car.
If you have no spare fob at all, that is worth noting for later rather than now. A second fob programmed while nothing is wrong is a scheduled expense. A second fob programmed because the first one died is an urgent one, and urgency is the most reliable way to pay more for the same work. The cost side of that decision, dealer against locksmith, is set out in our guide to key fob replacement in Canada.
The fob that only fails in one car park
A fob that dies in a particular underground car park and behaves perfectly two streets away has not failed. Something local is drowning it out. Move the vehicle a few metres and retest before you accept any diagnosis that involves paying somebody.
There is a version of this worth taking more seriously. If your fob will not lock the car outside your own home, and the car is later found unlocked or missing, the fob was not the problem. Police-reported motor vehicle theft in Canada fell 16% in 2025 to 83,652 incidents, or 201 per 100,000 population, the second consecutive annual decline (Statistics Canada, released 22 July 2026). Falling is not the same as rare, and the tooling has moved on.
Transport Canada acknowledged as much in a proposed amendment published on 27 December 2025, which would replace the 1998 immobilizer standard with ANSI/CAN/UL/ULC 338:2025 and UN Regulation No. 162. The proposal explicitly extends testing to electronic attack tools, naming on-board diagnostics key programmers, emulators and key signal relay equipment (Canada Gazette, Part I, Regulations Amending the Motor Vehicle Safety Regulations (Theft Protection), 27 December 2025). It is a proposal rather than law: compliance would be required two years after publication in Part II.
For a driver, the practical consequence is small and specific. Check the car is actually locked rather than assuming the button worked, and treat a fob that fails only at home as worth mentioning to police rather than worth replacing.
What to ask before anyone touches it
Once you have ruled out the cell and identified whether the fob or the vehicle is at fault, the remaining question is who to call and what to establish before they arrive. Fob work is booked labour, and booked labour is quotable in advance.
- Whether the quoted figure covers the fob, the programming, and the callout, or only one of the three
- Whether they have the equipment for your make, model and year, confirmed before the visit rather than in your driveway
- What happens to the price if the fault turns out to be the vehicle rather than the fob
- What proof of ownership they will need, since anyone who will pair a new device to your immobilization system should be asking for it
- Whether the existing fob will be deauthorized, which matters if you lost it rather than broke it
- The legal business name, and the licence number in provinces that issue one
Locksmith licensing requirements differ by province, so what there is to ask for depends on where you are standing. What we check on each listing, and how often we re-check it, is set out on how we check listings. If a business quoted you one figure and invoiced another, tell us so the entry can be corrected.
Frequently asked questions
My key fob stopped working. Is it always the battery?
It is the most common single cause and the cheapest to eliminate, which is why it goes first, but it is not always the answer. The sequence that separates the cases is cell, then spare fob, then vehicle power, then location. If a fresh cell of the correct printed code does not revive it and the spare fob works normally, you are looking at a fob fault rather than a flat cell.
Why can a fob not be copied like a house key?
Because there is nothing mechanical to copy. Canadian light vehicles built for sale after 1 September 2007 carry an immobilization system, and the standard behind it requires a minimum of 50,000 code variants (Canada Gazette, Part II, SOR/2011-69, Standard 114, 30 March 2011). A new fob has to be introduced to that system electronically by equipment that can talk to your specific vehicle, which is why it is a booking rather than a counter purchase.
The doors unlock but the car will not start. What does that mean?
That pattern usually separates the door side from the start side. Standard 114 describes an immobilization system that inhibits at least one electronic control unit so the vehicle cannot move under its own power, so a car that responds to the fob at the door and then refuses to turn over is behaving the way the regulation describes rather than failing at random. Say exactly that when you call, because it changes who you should be calling.
Should I go to the dealer or an auto locksmith?
Both do this work, and which one can do it for your vehicle depends on the make, model and year, so the question to settle on the phone is whether they have the equipment for yours. Ask for the total in advance either way. Requirements for locksmiths differ by province, which is part of what how we check listings exists to make visible.
My fob only fails at home. Is that a security problem?
It might be, and it is worth ten seconds of your attention rather than a repair booking. Interference from something nearby is the ordinary explanation. The less ordinary one is a device between you and the car, which is a live enough concern that a proposed federal amendment published on 27 December 2025 would extend immobilizer testing to key signal relay equipment. Either way, check the doors physically rather than trusting the button, and report a car you find unlocked.
Before you call anyone
Do the two minute sequence. Fresh cell of the exact printed code, then the spare fob, then a glance at the interior lights, then move the car and try again. Four checks, no tools, and at the end of them you know whether you are buying a coin cell, booking a locksmith, or booking a garage. Skipping the sequence does not save time. It moves the diagnosis to somebody who is charging for it.
When it does turn out to be work you have to pay for, start from the businesses covering your area in the provincial directory, and begin with the ones whose pricing you can read before you call. Every guide we publish sits in the guides library.