Mitsubishi Key Fob Battery Replacement: CR1620 for Most Keys, CR2032 for the New Outlander
Most Mitsubishi keys take a small CR1620 battery, not the CR2032 that most other brands use. That covers the remote head keys on the Lancer, Outlander, Outlander Sport, Mirage and Eclipse Cross, and the FAST key (push-button start) used from 2007 to 2021. The 2022 and newer Outlander and Outlander PHEV, which share their key with Nissan, take a CR2032. Open a remote head key at the notch on the seam; open a FAST key by pulling out the emergency blade and levering at the slot. Fit the new cell the same way round as the old one. No reprogramming is needed.
Mitsubishi is the brand where owners most often come home with the wrong battery. Nearly every guide on the internet says CR2032 because that is what most cars take, but a CR2032 is 20 mm across and the holder in a Mitsubishi key is made for a 16 mm cell. It will not fit. This guide tells you which battery each Mitsubishi key actually takes, shows where each type opens, and covers what to do if the car still does not see the key afterwards.
Which battery your Mitsubishi key fob takes
The battery depends on the style of key. 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 tells you which family it belongs to.
| Key style | Typical FCC ID | Common on | Battery |
|---|---|---|---|
| Separate remote on the key ring | OUCG8D-620M-A, HYQ12ABA, GQ43VT19T | Galant, Eclipse, Endeavor, Lancer and Montero, roughly 2000 to 2012 | CR1620 on the OUCG8D type; the older square remotes take a CR2032, so read the old cell |
| Remote head key (buttons on the key head, turn-key ignition) | OUCG8D-625M-A, OUCJ166N, OUC644M-KEY-N | Lancer 2008 to 2017, Outlander 2007 to 2020, Outlander Sport and RVR 2011 to 2024, Mirage 2014 to 2024, Eclipse Cross 2018 to 2024, i-MiEV | CR1620 |
| FAST key with push-button start | OUC644M-KEY-N, GHR-M004, GHR-M003 | Outlander 2007 to 2021, Lancer and Lancer Evolution 2008 to 2017, Outlander Sport 2011 to 2024, Eclipse Cross 2018 to 2024, Mirage G4 (higher trims) | CR1620 |
| Smart key shared with Nissan | KR5MTXN1, KR5TXN7 | Outlander 2022 on, Outlander PHEV 2023 on | CR2032 |
The code stamped on the flat + face of the old battery is the final word. A CR1620 is 16 mm across and 2 mm thick; a CR1616 is the same width but thinner and will work badly; a CR2032 will not fit at all. If the old battery is missing, the owner’s manual lists the type in the section on the keyless entry system or the FAST key.
The code tells you the size: the first two digits are the diameter in millimetres and the last two are the thickness in tenths of a millimetre. A CR1616 dropped into a CR1620 holder is 0.4 mm too thin and makes patchy contact, which shows up as a key that works from arm’s length one day and not at all the next. Our key fob battery size chart lists every size by brand.
What you need
- One new battery of the exact code printed on the old one (Panasonic, Energizer, Duracell, Murata or Mitsubishi branded all work; CR1620 is less common in shops, so buy it before you open the key)
- A small flat-blade screwdriver, a coin, or a plastic pry tool, and a small Phillips screwdriver for the remote head key
- A clean table and good light, so a dropped battery or the small rubber button pad does not vanish
Avoid rechargeable cells. 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 Mitsubishi FAST key
This covers the push-button start key used from 2007 to 2024 on the Outlander, Lancer, Outlander Sport and Eclipse Cross, which takes a CR1620, and the 2022 and newer Outlander smart key, which opens the same way but takes a CR2032.
Slide the small catch on the back of the key and pull the metal key blade straight out. You will use its tip in the next step.
Look into the opening the blade came from. There is a small notch between the two halves. Push the tip of the blade or a flat screwdriver into that notch and twist gently; the back cover lifts off from that end. Do not pry around the outside seam.
Before you touch the battery, look at which side shows. On Mitsubishi keys the + side with the code printed on it normally faces up, towards the back cover, but take a photo so there is no guessing later.
Use a plastic tool or the tip of the blade at the small cut-out beside the battery to lever it up, and 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 blade home until it clicks, and press lock and unlock. The lights should flash and the small LED on the key should blink 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 Mitsubishi remote head key
This is the key with the buttons on the plastic head of a fixed metal blade, used on turn-key Lancers, Outlanders, Outlander Sports, Mirages and Eclipse Crosses. It takes a CR1620.
- Turn the key over. There is a small Phillips screw in the back of the head on most versions; remove it. On versions without a screw, find the notch on the seam at the bottom edge of the head.
- Put a coin or the tip of a flat screwdriver 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. On these keys the + side usually faces the circuit board, which catches people out.
- Press in the new CR1620 the same way round, check the rubber button pad is seated, snap the halves together until the seam is flush all the way round, and refit the screw.
The transponder chip that lets the car start is sealed in the key head and does not use the battery. So even with a completely dead remote the key still turns the ignition and starts the engine; you just have to unlock the door by hand.
3V lithium CR1620 coin cell
For most Mitsubishi keys. The 2022 and newer Outlander takes a CR2032. Buy a name brand in a small multi-pack and keep the spares in the glove box, not loose in the key.
Other size: CR2032
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Do you need to reprogram a Mitsubishi 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 Mitsubishi key keeps working as soon as a fresh cell goes in. If the instrument panel showed a key battery warning, it clears after the next start or two. If a remote head key has lost its sync after months without power, turn the key in the ignition and press a button once; the car picks it up again.
If the car still does not see the key
First, get moving. On a Mitsubishi with push-button start, hold the FAST key with its buttons facing you and touch the back of the key to the engine switch, or on older Outlanders and Lancers hold it against the switch for a few seconds, then press the brake and press the switch; the car reads the chip through the button. The 2022 and newer Outlander works the same way. The emergency 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 CR1616 in a CR1620 holder makes patchy contact and the key works one day and not the next. 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. The remote head key is the one people most often get wrong.
- 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. Small cells like the CR1620 sit on shop shelves for a long time and 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 key that has been dropped hard, through a wash, or left on a hot dashboard can have a cracked solder joint or corroded board. A locksmith can test whether it still transmits.
If the buttons work but the car does not respond, the full checklist is in key fob not working after a battery replacement.
What it costs
A Mitsubishi dealer parts counter will usually fit a battery while you wait for the cost of the cell plus a small labour charge. The larger figures only apply if the key itself has to be replaced. Mitsubishi remote head keys are among the cheaper keys to replace because many locksmiths stock them; the FAST key has to be programmed with dealer-level tools, which is why it costs more.
How long the new battery will last
A remote head key only transmits when you press a button, but the CR1620 is a small cell, so expect two to three years rather than the four or five a CR2032 gives in a bigger key. A FAST key listens for the car and answers whenever you touch a door handle, so expect one to two years from it, and the same from the CR2032 in the new Outlander smart key. Cold weather, keeping the key within a few metres of the car overnight, and carrying it loose with things that press the buttons all shorten that. More detail is in how long key fob batteries last.
Safety: keep coin batteries away from children and pets
A swallowed coin cell can cause serious internal burns within hours, and the small CR1620 is an easy size to swallow. 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
Most Mitsubishi keys, including the remote head keys and the FAST key with push-button start, take a CR1620. The 2022 and newer Outlander and Outlander PHEV take a CR2032. Confirm with the code printed on the old battery.
Not in a key designed for a CR1620. A CR2032 is 20 mm across and the holder is made for a 16 mm cell, so it will not fit. Only the 2022 and newer Outlander smart key takes a CR2032.
Slide the catch and pull out the emergency blade, then push the tip of the blade or a small flat screwdriver into the notch inside the slot it came from and twist. The back cover lifts off. Do not pry at the outside seam.
No. Mitsubishi keys keep their pairing without battery power. The key works as soon as the new battery is in, and any key battery warning clears after the next start or two.
Hold the FAST key against the engine start switch, with the buttons facing you, press the brake and press the switch. The car reads the chip in the key through the switch. Use the emergency blade to unlock the driver’s door.
It fits, but it is 0.4 mm thinner, so the contact is poor and the key becomes unreliable. Use a CR1620.