How to replace a Honda key fob battery is a five-minute job if you open the shell the way it was designed to open. Most proximity fobs from the last decade split with a coin after you slide the emergency key out. Older flip keys and remote heads use a small screw or a sliding door and a thinner cell.
You do not program the fob afterward. Honda keys keep their code when the cell is out. If the car ignores the fob after a careful swap, the usual causes are a reversed cell, a crushed contact, a cracked shell, or a cell that is not the number printed on the old one.
The battery, stated plainly
| What this page covers | how to replace a honda key fob battery |
|---|---|
| Battery to buy | CR2032 on most smart fobs; CR1616 on many older remotes |
| Fob you are likely holding | Depends on the year: smart key or flip remote |
| Cell type | 3-volt lithium coin cell. Do not use a rechargeable LIR cell. |
| Programming after the swap | Not required when you only change the battery. |
Work on a table, not over a sink. Slide the mechanical emergency key out first and put it in your pocket. That key still opens the driver door if the shell will not close. The release is a latch on the back or side of a smart fob. Flip keys are different: look for a screw before you twist anything.
The smart-fob seam is the slot the emergency key just left. A United States quarter, a Canadian toonie, or a one-euro coin fits the notch. Twist gently. The housing pops into a button half and a back half. Leave the rubber button mat where it sits. If you flip that mat, the buttons feel wrong and the shell may not click shut.
Read the cell before you buy a replacement. A CR2032 is 20 mm across and 3.2 mm thick. A CR2025 is the same width but thinner. A CR1616 is smaller, about 16 mm, and it is what many Honda remotes from the mid-2000s through the early 2010s use. A cell that “almost” fits will sit in the cup and still fail to touch both contacts.
Polarity is marked inside the shell. On a lot of Honda smart fobs the plus face points toward the buttons, but the molded plus and minus signs are the instruction, not a forum post. A rechargeable LIR2032 is the wrong part. It is 3.6 volts. The fob wants a 3-volt lithium CR cell.
Do not bend the little metal finger that presses on the cell. If you flatten it, a brand-new battery still will not power the circuit. Lift the old cell with a fingernail or a plastic card. Wipe the new cell with a dry cloth so oil from your skin is not on the face. Press it in until the clip holds it. Squeeze the shell until both sides click, return the emergency key, and only then test the car.
Changing the cell
Stand at the curb, not in your kitchen. Lock, unlock, then lock again. Walk back a few car lengths and repeat. A healthy smart fob should work from several meters. If it only works when it touches the door, the cell is weak, backward, or not making contact.
On a flip key, the cover is a screw or a slide, not a coin slot. Put a cloth under the fob so the screw cannot bounce away. Match CR1616 with CR1616. Tighten the screw until it is snug. Crushing the housing cracks the plastic around the screw boss.
The full model-by-model chart of which cell Honda used is on the battery size chart. Use this page for the motion of the swap, and that chart when you are standing in a store aisle.
If the fob still misbehaves
A fob that does nothing after a swap still has the immobilizer chip. You can start the car by holding the fob against the start button while you press the brake. That procedure is covered on its own page because a dead cell and a broken fob feel the same until you try it.
If the shell cracked, the buttons will feel mushy and water will get in the next time it rains. Stop and look at a replacement shell or a dealer fob before you force it. Forcing a broken hook makes the repair more expensive than the battery ever was.
Range that collapses again within a week is not normal aging. Ordinary Honda fobs last about two to four years. Rapid drain on some push-button cars has been cured by a dealer checking for a key-fob update, not by buying a third cell.
What to spend, and what not to buy
A single name-brand CR2032 from Panasonic, Murata, Energizer, or Duracell is enough. Expect a few dollars in a shop and less in a two-pack. Dealer service counters often charge labor on top, which is why the same job is a parts-counter visit for some people and a coin-on-the-kitchen-table job for others.
Skip no-name cells sold in a bag of twenty for the price of a coffee. They sag under the short, sharp current a fob transmitter uses, and the date code is often unreadable. Skip anything labeled LIR2032.
Related guides
- What Battery Does a Honda Key Fob Take?
- Honda Key Fob Battery Size Chart
- Start a Honda With a Dead Key Fob Battery
- Honda Key Fob Not Working After Battery Change
Questions people ask
Do you have to reprogram a Honda key fob after a battery change?
No. Changing the coin cell does not clear the fob. Reprogramming is for a new or used fob the car has never learned.
Which side is positive on a Honda key fob battery?
Follow the plus and minus marks molded in the shell. On many smart fobs the plus side faces the buttons, but the mark in your fob is the one that counts.
Can I use CR2025 instead of CR2032?
Only if the old cell says CR2025. A CR2025 is thinner. It will rattle or lose contact in a CR2032 holder.
Honda is a trademark of Honda Motor Co., Ltd. Honda Key Fob Battery is an independent guide and is not affiliated with, endorsed by, or sponsored by Honda. The code printed on the cell already in your fob overrides any chart. A fob bought later, or a car sold in another country, can use a different shell.