Toyota Key Fob Battery Replacement: Which Battery (CR2016, CR1632, CR2032, CR2450) and How to Change It
Toyota uses four different coin cells, so read the code on the old battery before you buy: CR2016 in remote head keys (buttons on the key itself), CR1632 in most oval smart keys from about 2007 to 2020, CR2032 in the 2019 to 2024 generation of smart keys (RAV4, Highlander, Corolla, Camry), and CR2450 in the newer flat, rectangular keys (Corolla Cross, Tundra, Sequoia, Grand Highlander, 2025 Camry). To open a smart key, slide out the emergency key, put a flat tool in the slot it came from, twist, and lift the battery out with the + side noted. No reprogramming is needed afterwards.
Changing the battery in a Toyota key fob takes about five minutes and costs a few dollars. The only real way to get it wrong is to buy the wrong battery, and that happens a lot with Toyota because the company has used four sizes across its keys. This guide tells you which one your key takes, how to open each type of Toyota key without cracking it, and what to do if the car still does not see the key afterwards.
Which battery your Toyota key fob takes
The battery depends on the style of key, not just the model year. Find your key in the table, then confirm the code against the old battery once the case is open. The FCC ID printed on the back of the fob is the quickest way to tell which family your key belongs to.
| Key style | Typical FCC ID | Common on | Battery |
|---|---|---|---|
| Remote head key (buttons built into the key, no push-button start) | HYQ12BBY, GQ4-29T, HYQ12BDM, HYQ12BEL | Camry 2007 to 2017, Corolla 2008 to 2019, RAV4 to 2018, Tacoma, Tundra, Sienna, Highlander, Yaris, Avalon (non smart-key trims) | CR2016 |
| Oval smart key, older generation | HYQ14AAB, HYQ14ACX, HYQ14FBA, HYQ14AEM | Prius 2010 to 2015, Camry 2012 to 2017, Avalon 2013 to 2018, RAV4 2013 to 2018, Highlander 2014 to 2019, Tacoma 2016 to 2023, 4Runner, Sienna 2011 to 2020 | CR1632 |
| Oval smart key, 2019 to 2024 generation | HYQ14FBC, HYQ14FBE, HYQ14FBX (oval) | RAV4 2019 to 2025, Corolla 2020 on, Highlander 2020 to 2024, Camry 2018 to 2024, Sienna 2021 on, Venza | CR2032 |
| Flat rectangular smart key (newest design) | HYQ14FBW, HYQ14FBX (flat) | Corolla Cross 2022 on, Tundra 2022 on, Sequoia 2023 on, Grand Highlander, Crown, bZ4X, Camry 2025 on, Land Cruiser 2024 on | CR2450 |
Several of these keys look almost the same from the outside. The code stamped on the flat + face of the old battery is the final word. If the old battery is missing or unreadable, the owner’s manual lists the type in the section on the smart key or wireless remote.
If you want to understand what the numbers mean, the first two digits are the diameter in millimetres and the last two are the thickness in tenths of a millimetre. A CR1632 is 16 mm wide and 3.2 mm thick; a CR2032 is 20 mm wide and the same thickness. That is why a CR2032 will not drop into a CR1632 holder, and why a CR2025 in a CR2032 holder sits loose. Our key fob battery size chart covers every size you are likely to meet.
What you need
- One new battery of the exact code printed on the old one (Panasonic, Energizer, Duracell, Sony/Murata or Toyota branded all work)
- A small flat-blade screwdriver, a coin, or a plastic pry tool
- A clean table and good light, so a dropped battery or the small rubber button pad does not vanish
Avoid rechargeable cells such as LIR2032. They have the right shape but a higher voltage, and they are not what the key is designed for. A branded 3 V lithium cell with a date well into the future is all you need.
Changing the battery in a Toyota smart key
This covers the oval keys (CR1632 or CR2032) and the newer flat keys (CR2450). The procedure is the same; only the battery differs.
Slide the small catch on the side or back of the fob and pull the metal key blade straight out. Put it somewhere safe; you will use its tip in the next step.
Look into the slot the emergency key came out of. There is a small notch for a flat tool. Push the tip of the key blade or a flat screwdriver into that notch and twist gently. The back cover pops off in one piece. Do not pry around the outside seam; that is how cases get chewed up.
Before you touch the battery, look at which side shows. On Toyota smart keys the + side (the one with the code printed on it) normally faces up, towards you, but take a photo so there is no guessing later.
Use the tip of the emergency key or a plastic tool at the small cut-out beside the battery to lever it up. Lift it out by the edge. Do not slide a metal tool across the circuit board.
Hold the new cell by its edges and press it into the holder the same way round as the old one. It should sit flat and click under the retaining tab. A battery that rocks or stands proud is the wrong size.
Snap the cover back on, slide the emergency key home until it clicks, and press lock and unlock. On a working key the small LED flashes with each press.
If the rubber button pad came away with the cover, lay it back in the front half first, buttons facing out, before you close the case. A pinched pad is why buttons feel mushy after a battery change.
Changing the battery in a Toyota remote head key
These are the keys where the buttons sit on the plastic head of the metal key. They take a thin CR2016.
- Find the small notch on the seam of the key head, usually on the side near the key blade or at the bottom edge. A few older Toyota remotes have a tiny Phillips screw on the back instead; remove it first.
- Put the tip of a flat screwdriver or a coin in the notch and twist. Work the two halves apart slowly rather than forcing one spot.
- Note which way the battery faces, then lever it out from the cut-out at its edge.
- Press in the new CR2016 the same way round, check the small rubber button pad is seated, and snap the halves together until the seam is flush all the way round.
The transponder chip that lets the car start is sealed in the key head and does not use the battery. So even if the remote buttons are dead, the key will still turn the ignition and start the engine.
3V lithium coin cell in the size printed on your old battery
Toyota keys take CR2016, CR1632, CR2032 or CR2450 depending on the key. Buy a name brand in a small multi-pack and keep the spares in the glove box, not in the fob.
Other sizes: CR1632 · CR2450 · CR2016
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Do you need to reprogram a Toyota key after a battery change?
No. The pairing between the key and the car is stored in memory that does not depend on the battery, so a Toyota key keeps working as soon as a fresh cell goes in. If the dashboard showed a Key battery is low, replace message, it normally clears after the next time you start the car. If it stays on, use the key a few times over a day or two; the car re-reads the battery state during normal use. Our guide to the low battery warning that stays on after a new battery covers what to check if it does not.
If the car still does not see the key
First, get moving. Every push-button Toyota has a backup: hold the fob with the Toyota logo side touching the Start button. You will hear a beep, which means the car has read the chip in the key through the button. Press the brake and push Start within a few seconds. The emergency key blade opens the driver’s door if the remote lock does not respond.
Then work through the usual causes, in order of how often they turn out to be the problem:
- Wrong size. A CR2025 or CR2016 in a CR2032 holder makes patchy contact; a CR1632 in a CR2032 key rattles. Compare the code on the new cell with the old one.
- Upside down. If the key does nothing at all and the LED does not flash, open it and turn the battery over.
- Bent or dirty contact. The spring contact can be flattened by prying. Lift it gently with a plastic tool and clean it with a dry cotton bud. See how to clean key fob battery contacts.
- Tired new battery. Cells that sat in a drawer or came from an unbranded multi-pack can be flat out of the packet. Try a second one from a fresh pack.
- The car’s 12 V battery. If the car was also slow to crank or the dash lights were dim, the problem is the car, not the key. See can a bad car battery cause key fob problems.
- Damage inside the key. A fob that has been dropped hard, through a wash, or left in a hot car can have a cracked solder joint or corroded board. A locksmith can test whether it still transmits.
The full checklist is in key fob not working after a battery replacement.
What it costs
Many Toyota parts counters will fit a battery while you wait for the cost of the cell plus a small charge, and a few do it free during a service. The larger figures only apply if the key itself has to be replaced, which a battery change almost never leads to.
How long the new battery will last
A remote head key only transmits when you press a button, so a CR2016 in one typically lasts three years or more. A smart key listens for the car and answers whenever you touch a door handle, so expect one to two years from a CR1632 and a little longer from a CR2032 or CR2450. Toyota’s own guidance is that the battery lasts roughly one to two years in a smart key, which matches what most owners see. Cold weather, keeping the key within a metre or so of the car overnight, and carrying it loose with items that press the buttons all shorten that. More detail is in how long key fob batteries last.
Newer Toyotas have a battery-saving mode for the smart key: press and hold the lock button, then press unlock twice while still holding lock. The LED flashes four times and the key stops listening for the car until you press any button. It is worth using if a key will sit unused for weeks.
Safety: keep coin batteries away from children and pets
A swallowed coin cell can cause serious internal burns within hours. Keep spares and the old cell out of reach, and dispose of old batteries at a drop-off point rather than in household waste. If you think a child has swallowed a battery, go to the emergency room straight away and call the National Battery Ingestion Hotline at 1-800-498-8666, or Poison Help at 1-800-222-1222.
Frequently Asked Questions
It depends on the key. Remote head keys take a CR2016, most oval smart keys from 2007 to 2020 take a CR1632, the 2019 to 2024 smart keys take a CR2032, and the newest flat rectangular keys take a CR2450. Always confirm with the code on the old battery.
Slide the catch and remove the emergency key, then push the tip of that key or a small flat screwdriver into the notch inside the slot it came from and twist. The back cover pops off. Do not pry at the outside seam.
No. Toyota keys keep their pairing without battery power. The key works as soon as the new battery is in, and any low battery warning clears after the next start or two.
Hold the fob with the Toyota logo side against the Start button until you hear a beep, then press the brake and push Start within a few seconds. Use the emergency key blade to unlock the driver’s door.
No. A CR2032 is wider than a CR1632 and will not fit the holder, and it is thicker than a CR2025 so the case may not close. Use the exact code the key was designed for.
The car usually needs a start cycle or a day of normal use to update. If it stays on, check that the new cell is the right size, the right way up, and from a fresh pack, and that the contact spring is not flattened.