Honda Key Fob Battery Replacement: Which Battery (CR2032, CR1616, CR1620) and How to Change It
Honda key fobs use three batteries: CR2032 in every Honda smart key with push-button start, CR1616 in the older remote head keys (roughly 2003 to 2013), and CR1620 in the later remote head keys (roughly 2013 to 2021). To change a smart key battery, slide the catch, pull out the emergency key, put a flat tool in the slot it came from and twist; the back cover pops off and the battery lifts out with the + side facing you. Remote head keys usually have one small Phillips screw on the back, then split at the seam. No reprogramming is needed.
A Honda key fob battery is one of the cheapest fixes on the car, and the only way to get it wrong is to buy the wrong size. Honda has used three coin cells across its remotes, and two of them (CR1616 and CR1620) look identical until you read the code. This guide tells you which battery your Honda key takes, how to open both styles of key without marking the case, and what to check if the car still says the key is not detected afterwards.
Which battery your Honda key fob takes
The battery follows the style of key more than the model year. Check which one you have, then confirm against the code printed on the old battery once the case is open. The FCC ID on the back of the fob tells you the family.
| Key style | Typical FCC ID | Common on | Battery |
|---|---|---|---|
| Older remote head key (buttons on the key, no push-button start) | OUCG8D-380H-A, N5F-S0084A, MLBHLIK-1T, N5F-A05TAA | Accord 2003 to 2012, Civic 2006 to 2013, CR-V 2007 to 2013, Odyssey 2005 to 2010 (separate remote), Pilot 2009 to 2015, Fit 2009 to 2014, Ridgeline 2006 to 2014 | CR1616 |
| Later remote head key | MLBHLIK6-1T, MLBHLIK6-1TA | Civic 2014 to 2021 (keyed trims), Accord 2013 to 2017 (keyed trims), CR-V 2014 to 2016 LX, HR-V 2016 to 2022, Fit 2015 to 2020, Odyssey 2011 to 2017 (separate remote) | CR1620 |
| Smart key (push-button start) | KR5V1X, KR5V2X, ACJ932HK1210A, KR5T4X, KR5TP-4 | Accord 2013 on, Civic 2016 on, CR-V 2015 on, Pilot 2016 on, Odyssey 2018 on, Ridgeline 2017 on, Passport, HR-V 2023 on, Prologue | CR2032 |
CR1616 and CR1620 are both 16 mm across; the difference is 1.6 mm against 2.0 mm thick. A CR1620 forced into a CR1616 key stops the case closing properly, and a CR1616 in a CR1620 key sits loose and gives patchy range. Read the code on the old battery rather than guessing from the year.
If you are curious 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. Our key fob battery size chart covers every common size.
What you need
- One new battery of the exact code on the old one (Panasonic, Energizer, Duracell or Murata; Honda dealers sell the same cells in Honda packaging)
- A small flat-blade screwdriver or a plastic pry tool
- A small Phillips screwdriver for remote head keys
- A clean surface with good light, so the small 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 Honda smart key
This is the fob with the emergency key hidden inside it, used on push-button start models.
Slide the release catch on the 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 tip of the key blade or a small flat screwdriver into it and twist gently. The back cover lifts away. Prying around the outer seam is what leaves teeth marks on the case, so stay in the slot.
On Honda smart keys the + side of the CR2032 (the side with the code printed on it) faces up, towards you, once the cover is off. Take a photo before you remove it.
Use the key tip or a plastic tool at the small cut-out beside the battery and lever it up. Lift it out by the edge. Do not drag a metal tool across the circuit board.
Hold the new cell by its edge and press it in the same way round. It should sit flat under the retaining tab without rocking.
Snap the cover on, slide the emergency key back in until it clicks, and press lock and unlock. The small LED flashes with each press when the battery is good.
If the buttons feel soft or do not click afterwards, open the fob again and reseat the rubber button pad in the front half. It is easy to trap an edge of it when the case closes.
Changing the battery in a Honda remote head key
These are the keys where the lock and unlock buttons sit on the plastic head of the key itself. They take a thin CR1616 or CR1620.
- Turn the key over. Most Honda remote head keys have one small Phillips screw on the back. Remove it and keep it on a piece of tape.
- Put the tip of a flat screwdriver into the seam at the end of the key head and twist gently. Work along the seam until the two halves separate. On keys without a screw, the seam has a small notch to start from.
- Note which way up the battery sits, then lever it out from the cut-out at its edge.
- Press in the new battery the same way round, make sure the rubber button pad is seated, and snap the halves together. Replace the screw and do it up snug, not tight.
The immobilizer chip that lets the car start is sealed in the key head and does not use the battery. A Honda remote head key with a dead battery will still turn the ignition and start the engine; you just lose the remote buttons until the battery is changed.
CR2032 3V lithium coin battery (Honda smart keys)
Every Honda push-button-start key takes a CR2032. Buy a name brand in a small multi-pack and keep the spares in the glove box. Remote head keys take a CR1616 or CR1620 instead; see the links below.
Remote head keys: CR1616 · CR1620
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Do you need to reprogram a Honda key after a battery change?
No. The pairing is stored in memory that does not need battery power, so the key works the moment the new cell is in. If the dash showed Keyless Remote Battery Low on the information display, it clears after the next start or two. Honda only needs programming when a key is new to the car, or when all keys have been lost.
If the car still says the key is not detected
First, start the car. On any push-button Honda, hold the fob so its buttons face you and touch it to the Engine Start/Stop button. The car beeps and the button light turns green; press the brake and push the button within about ten seconds. The emergency key blade opens the driver’s door if the remote lock is dead.
Then check, in this order:
- Battery size. A CR2025 or CR2016 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. Open the fob and turn it over.
- 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, 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 dashboard 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 Honda keyless remote not working and key fob not working after a battery replacement.
What it costs
Most Honda parts counters will fit a battery while you wait for the price of the cell plus a few dollars, and some do it free 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 remote head key only transmits when you press a button, so a CR1616 or CR1620 normally lasts two to four years. A smart key listens for the car and answers every time you touch a door handle, so a CR2032 in one typically lasts one to two years. Cold winters, leaving the fob within a few feet of the car overnight, and carrying it loose where items press the buttons all shorten that. See how long key fob batteries last for a sensible replacement schedule.
If a smart key is going to sit unused for weeks, say a spare in a drawer, store it well away from the car so it is not constantly answering the car’s signal.
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
Honda smart keys with push-button start use a CR2032. Older remote head keys (about 2003 to 2013) use a CR1616, and later remote head keys (about 2013 to 2021) use a CR1620. Confirm with the code printed on the old battery.
No. Honda keys keep their pairing without battery power. The key works as soon as the new battery is in, and the Keyless Remote Battery Low message clears after the next start or two.
Slide the catch and remove the emergency key, then push the tip of the key or a small flat screwdriver into the notch inside the slot it came from and twist. The back cover lifts off.
Hold the fob with the buttons facing you against the Engine Start/Stop button until the car beeps, then press the brake and push the button within about ten seconds. Use the emergency key blade to open the driver’s door.
Not reliably. The CR1620 is 0.4 mm thicker, which can stop a CR1616 key from closing properly, and a CR1616 in a CR1620 key sits loose. Use the code the key was designed for.
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. If the fob LED flashes but the car ignores it, use the backup start and have a locksmith test the fob.