Lexus Key Fob Battery Replacement: Which Battery (CR1632, CR2032, CR2016, CR2412) and How to Change It
Most Lexus smart keys from about 2006 to 2020 take a CR1632, which is the one people get wrong because it is narrower than the common CR2032. Newer keys take a CR2032 (ES, UX, IS and others from about 2018) or a CR2450 (the flat rectangular key on the newest NX, RX, TX, GX and LX). The slim card key takes a CR2412, and the old remote head key with the blade attached takes a CR2016. Read the code on the old battery before you buy. To open a smart key, slide the catch and pull out the emergency key, then twist a flat tool in the slot it came from. Fit the new battery the same way round, close the case and press lock to test. No reprogramming is needed.
Lexus keys share their hardware with Toyota, which means the same mix of battery sizes. The job is a five-minute one, but buying a CR2032 for a key that wants a CR1632 is the most common mistake we hear about, because the 20 mm cell simply will not drop into the 16 mm holder. This guide tells you which battery each Lexus key takes, how to open each style without marking it, how to start the car when the key is dead, and what to check if a new battery does not bring it back.
Which battery your Lexus key fob takes
| Key style | Typical FCC ID | Common on | Battery |
|---|---|---|---|
| Remote head key (buttons on the key, blade attached) | HYQ12BBT, HYQ1512V | ES 2002 to 2006, RX 2004 to 2009 (keyed), GX 2003 to 2009, LX 2003 to 2007, IS 2001 to 2005, SC | CR2016 |
| Smart key, 2006 to 2020 (rounded) | HYQ14AAB, HYQ14ACX, HYQ14AEM, HYQ14FBA, HYQ14FBB | ES 2007 to 2018, IS 2006 to 2020, GS 2006 to 2020, RX 2010 to 2022, NX 2015 to 2021, GX 2010 to 2023, LX 2008 to 2021, LS 2007 to 2017, CT, RC | CR1632 |
| Smart key, about 2018 on (rounded, newer electronics) | HYQ14FBF, HYQ14FBZ, HYQ14FLA | ES 2019 on, UX 2019 on, IS 2021 on, LC 2018 on (standard key), LS 2018 on (standard key) | CR2032 |
| Flat rectangular smart key (newest design) | HYQ14FBX, HYQ14FBW | NX 2022 on, RX 2023 on, TX, GX 2024 on, LX 2022 on, RZ | CR2450 |
| Card key (credit-card size) | HYQ14FBF-card, HYQ14ACX-card | Optional on LS, LC, ES, RX, NX and others | CR2412 |
Several of these keys look nearly identical from outside. The code stamped on the flat + face of the old battery is the final word; the owner’s manual lists it under the electronic key section. CR1632 (16 mm) and CR2032 (20 mm) are not interchangeable in either direction.
The first two digits of a coin cell code are the diameter in millimetres and the last two are the thickness in tenths of a millimetre. Our key fob battery size chart covers every common size, and the Toyota guide covers the same key families on Toyota models.
What you need
- One new battery of the exact code on the old one. Panasonic, Energizer, Duracell, Murata or Lexus branded
- A small flat-blade screwdriver or a plastic pry tool; a coin works on the remote head key
- A clean surface with good light so the rubber button pad does not go missing
Skip rechargeable LIR cells. They have the same shape but a higher voltage than the key is built for.
Changing the battery in a Lexus smart key
The procedure is the same for the rounded keys (CR1632 or CR2032) and the newer flat key (CR2450); only the battery differs.
Slide the small catch on the side or back of the fob and pull the metal key straight out. You will use its tip in the next step.
Look into the slot the emergency key came out of. There is a notch for a flat tool. Put the key tip or a small flat screwdriver into it and twist gently. The back cover pops off in one piece. Do not pry at the outer seam; that is how cases get chewed.
On Lexus smart keys the + side with the code normally faces up towards you once the cover is off. Take a photo before you touch it.
Lever it up at the cut-out beside it with the key tip or a plastic tool and lift it out by the edge. Do not slide a metal tool across the circuit board.
Hold it by the edge and press it in the same way round. 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. The LED flashes with each press when the battery is good.
The card key and the remote head key
Card key (CR2412): slide the small lock on the edge and pull out the mechanical key, then push the exposed battery tray out of the side of the card with the key tip. The tray holds a thin CR2412. Fit the new one the same way round and push the tray back until it clicks. The CR2412 is harder to find in shops than the other sizes; order it ahead rather than waiting for the card to die.
Remote head key (CR2016): find the small notch on the seam of the key head, usually on the side near the blade. Put a coin or flat screwdriver in it and twist. Note which way the CR2016 faces, swap it, check the button pad is seated and snap the halves together. The transponder chip that starts the car is sealed in the head and does not use the battery, so a remote head key with a dead battery still starts the engine.
CR1632 3V lithium coin battery (most 2006 to 2020 Lexus smart keys)
Most Lexus smart keys take the narrower CR1632, not a CR2032. Newer keys take CR2032 or CR2450 and the card key takes CR2412; see the links below. Buy a name brand and check the date on the pack.
Other Lexus keys: CR2032 · CR2450 · CR2412 · CR2016
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Do you need to reprogram a Lexus key after a battery change?
No. The pairing is stored in memory that does not need battery power, so the key works as soon as the new cell is in. If the dash showed Key battery is low, replace, the message normally clears after the next start; if it lingers, use the key normally for a day or two. Programming is only needed for a key that is new to the car.
If the car still does not see the key
First, start the car. Hold the fob with the Lexus 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 card key works the same way held flat against the button. The emergency key blade opens the driver’s door.
Then check, in this order:
- Battery size. A CR1632 in a CR2032 key rattles; a CR2025 in a CR2032 holder makes patchy contact. Compare the new code with the old one.
- Battery upside down. No LED flash at all usually means the cell is reversed.
- Flattened contact. The spring contact can be pressed down while prying. Lift it gently with a plastic tool and wipe it with a dry cotton bud. See how to clean key fob battery contacts.
- A flat new battery. Unbranded multi-pack cells and cells that have sat for years can be dead in the packet. Try one from a fresh, dated pack.
- The car’s 12 V battery. If the car was also slow to crank or the dash was dim, the key is not the problem. See can a bad car battery cause key fob problems.
- Damage inside the fob. A fob that has been dropped hard, through the wash or left on a hot dash can have a cracked solder joint. A locksmith can test whether it still transmits before you pay for a new key.
The full checklist is in key fob not working after a battery replacement.
What it costs
Many Lexus dealers will fit a battery free or for the price of the cell during a service visit. The larger figures only apply when the key itself has to be replaced, which a battery change almost never leads to.
How long the new battery will last
A Lexus 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 and Lexus quote roughly one to two years. The card key’s small CR2412 tends to be at the short end. A remote head key only transmits when a button is pressed and its CR2016 usually lasts three years or more. Cold weather and keeping the key within a metre of the car overnight shorten all of these. See how long key fob batteries last.
Newer Lexus keys have a battery-saving mode: hold the lock button and press unlock twice while still holding lock. The LED flashes four times and the key stops listening for the car until any button is pressed. It is worth using on a spare key that sits in a drawer.
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 take old batteries to a drop-off point rather than 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
Most 2006 to 2020 Lexus smart keys take a CR1632. Keys from about 2018 on take a CR2032, the newest flat rectangular keys take a CR2450, the card key takes a CR2412 and the old remote head key takes a CR2016. Confirm with the code on the old battery.
No. The CR2032 is 20 mm across and the CR1632 holder is 16 mm, so it will not fit. Use the code the key was designed for.
Slide the catch and remove the emergency key, then twist the key tip or a small flat screwdriver in the notch inside the slot it came from. The back cover pops off. For the card key, remove the mechanical key and push the battery tray out of the side.
No. Lexus keys keep their pairing without battery power. The key works as soon as the new battery is in, and the low battery message clears after the next start or two.
Hold the fob with the Lexus 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 open the driver’s door.
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 was not flattened.