iPhone 12 トラブルシューティング

iPhone12がいつものようにボタンを長押ししても電源が入りません。

まず最初に、iPhoneが放電しているだけではないか、必ず確認してください。通常、iPhoneはバッテリーの残量が少なくなって電源が入らなくなると、接続を促す画面が表示されますが、バッテリーが極端に少なくなっている場合は、ディスプレイに電源を供給するためのエネルギーが不足している可能性があります。少なくとも10分間は電源プラグを差し込むようにして、iPhoneが放電していないことを確認してください。

Tip: Be sure to check that your cable, charging block, and outlet are all functional before ruling out simple discharge as the culprit. You can try plugging in another iPhone to make sure that the setup is getting power if you suspect that one of these components may be dysfunctional.

If your iPhone stops powering on for no apparent reason, i.e. you didn’t drop it, expose it to water, or sustain other damage to it since it last turned on, the most likely culprit is a firmware crash. You’ll need to perform a forced restart to get your phone out of a bad firmware loop, which you can do by following these steps:

1. Press and immediately release the volume up button.
2. Press and immediately release the volume down button.
3. Press and hold the power button.
4. The apple logo should show up after around 10 seconds—once it does, release the power button.

Note that these button presses must be performed in quick succession. Additionally, if your phone does not turn on as expected, you should try charging the phone for at least 10 minutes before trying again.

Over time, the batteries in smartphones will start to degrade and hold less and less charge over time. If you’ve been using your iPhone 12 excessively and have accumulated multiple thousands of charge cycles, your battery may have degraded to a point where it can no longer hold a charge.

Additionally, lithium-ion batteries like the one in your iPhone 12 don’t like to be kept at the extreme ends of their charge range (fully-charged or fully-discharged) for long periods of time. If you’ve kept your iPhone 12 at one of these extremes (especially fully discharged) for multiple weeks or months, this may have degraded the battery life significantly, even if your charge cycle count is relatively low.

You can check for battery issues by seeing if your phone turns on while plugged in. If your phone does turn on while connected to a power source, you can check the battery health using the following steps:

1. Open the Settings app on your phone.
2. Navigate to the Battery settings tab.
3. Select the Battery Health option from the Battery menu.
4. Check the Maximum Capacity percentage.
   • If this number is below 80%, your battery has degraded significantly and you’ll notice a shorter life per charge, but you should be able to continue using your iPhone.
   • If the number is below 50%, your battery is due for a replacement, as your battery’s maximum power output may be too low to handle the performance of your phone.

If you find that your battery is what’s causing your issues, you can replace it by following this nifty iPhone 12 Battery Replacement Guide.

The screen of the phone is responsible for displaying the user interface, and because it controls most of the input/output for the phone, a faulty screen may be mistaken for the phone not turning on.

If the phone was recently dropped and the screen is visibly damaged, a screen replacement may return the phone to working condition. However, you can test this by plugging the phone into an external display if possible. If you get an output on the external display, it means that your phone is still turning on, but the display is busted.

Another way to test for a damaged screen is to use a usb ammeter to confirm that the phone is charging, which confirms that the internals of the phone are still functional and points to an issue with the screen.

You can replace the screen by following this iPhone 12 Screen Replacement Guide.

If none of the above solutions were able to turn your iPhone 12 back on, the issue may be with the main circuit board of the phone. The motherboard controls most of the phone's functionality, handling input sent in from the screen and buttons and processing it to produce the desired outcome. Also contained on the motherboard are the phone’s A14 system-on-a-chip (containing the CPU, GPU, and RAM in one unit) and flash memory (which houses all of the phone’s data storage), among several other chips.

Typically, the motherboard only goes bad when it experiences a significant impact, exposure to water, extreme temperatures, or when the BIOS settings are changed (like when a jailbreak attempt is unsuccessful). If you suspect any of the above have damaged your motherboard, you may need to replace it to regain functionality for your phone.

You’re experiencing audio issues such as crackling sounds, loud static, intermittent or interrupted audio, choppy/garbled noises, or the device producing no sound at all

It’s entirely possible you just had a “looking for the keys that are in your hand” moment and forgot that you turned down your phone’s volume. With the volume muted, you obviously won’t be able to hear anything because your phone thinks you want it to be silent. Try turning the volume up using the upper button on the left side of the phone. If it worked, we won’t tell anyone about your facepalm moment.

This won’t be as much of a problem if you’re buying the most premium phone cases from Apple or Otterbox, but some cases can actually interrupt sound as it comes out of the speakers. Try removing the case and testing out the speakers again. If this fixes your sound issues, you may need to buy a new case, but at least you’ve identified the source of the problem.

Note: Although it may be a rare case, it is possible for a screen protector to obstruct sound coming from the earpiece speaker, so if you are having sound problems during calls and your screen protector doesn’t have a cutout for the smaller speaker at the top of the phone, you may need to remove the protector to properly diagnose the issue.

Sometimes the phone’s audio processor can glitch, causing the audio signals sent to the speaker to be corrupted. Try turning the bluetooth off and playing audio again. If this doesn’t help, perform a force restart on the phone and power the phone back on. If your phone’s audio is still suboptimal, you can likely rule out any software issues.

Some iPhone 12 and iPhone 12 Pro units contain a defective component in their receiver module which has a high chance of failing. If your phone has no trouble playing music or sound through the main speaker, but fails to produce sound through the receiver during calls, you may have one of these defective units.

Luckily, Apple has acknowledged this issue and has offered to fix affected phones through a service program. They specify that only models produced between October 2020 and April 2021 should be affected, so you may have trouble convincing them to extend the offer should your phone be manufactured outside the specified dates.

If your earpiece speaker is damaged through other means and is not eligible for Apple’s service program, you can use this iPhone 12 Earpiece Speaker and Front Sensor Assembly Replacement guide to do the fix yourself. However, you should be aware that replacing this module without Apple’s service technician software will disable FaceID on your device.

If your issue persists when playing sound through the main speaker, you may have a broken or clogged speaker unit. To solve the problem, first try cleaning out the speaker holes with a pin or toothpick. Blowing air into the speaker holes in short, controlled bursts may help to dislodge any stuck dust or debris.

If cleaning the speaker has no effect, the speaker may be physically damaged. You can replace it using this iPhone 12 Loudspeaker Replacement guide.

Your iPhone’s screen is on, but isn’t responding to touch input.

Occasionally, the operating system can glitch (especially when handling multiple compute-intensive tasks) causing the screen to freeze in place. If your screen is still in good condition, this is the likely culprit, and luckily your problems can be solved by performing a simple force reset. You can force reset your phone by executing the following steps:

1. Press and immediately release the volume up button.
2. Press and immediately release the volume down button.
3. Press and hold the power button.
4. The apple logo should show up after around 10 seconds—once it does, release the power button.

The digitizer is the component of the phone which handles touchscreen input. In modern screens like the one on the iPhone 12, the digitizer is integrated into the display assembly, fused together with the screen and display using heavy adhesives.

It’s possible to break this component while the display remains functional, allowing the phone to output visuals on the screen but disabling any touch input. Unfortunately, due to the glue, it becomes increasingly difficult to replace the digitizer separate from the screen. Instead, you’ll want to replace the entire display assembly, which can be done by following the steps in this iPhone 12 Screen Replacement guide.

Your phone has trouble sending or receiving text messages, you aren’t receiving certain messages from a group message thread, or your friends are getting mad at you for not responding to texts you never got.

A known software glitch in iOS is guilty of failing to display some texts to the iPhone 12. If you aren’t receiving certain texts that you know others are sending to you, you can try to fix the glitch by simply restarting the phone. To restart the phone:

1. Hold the right-side button along with either the volume up or volume down button until the “Slide to Power Off” prompt appears on the screen.
2. Slide the slider across the screen.
3. Once the phone has finished powering down, hold the right-side button until the Apple logo appears.

It’s also possible that the network itself is having trouble serving SMS data to your phone. To attempt to reset your phone’s connection to the network, you can try two things.

First off, you can reset the network settings to reestablish a connection with the network. To reset the network settings:

1. Open the Settings app on your phone.
2. Navigate to the General settings tab.
3. From the general settings tab, navigate to the Reset menu.
4. Select Reset Network Settings from the menu.
5. Type in your passcode if prompted.
6. Select “Reset Network Settings” once more from the warning prompt.

If reseting the network settings doesn’t work immediately, you can also try toggling iMessage settings to restart your phone’s connection with the network and Apple’s iMessage servers. To do this:

1. Open the Settings app.
2. Navigate to the Messages settings tab.
3. Toggle the iMessage slider at the top off for 10 seconds. Then turn it back on.
4. In the SMS/MMS section, toggle the MMS Messaging slider off for 10 seconds. Then turn it back on.

If neither of these solutions work, try performing a quick force restart on your phone. If none of these work, you should get in contact with your service provider, as the issue may be on their end.

Your phone’s camera is experiencing issues such as taking blurry photos or showing a blank screen on the camera app.

It’s possible that the problem isn’t with your camera’s hardware, but rather the software that you’re using is failing to produce a good image. This can be especially prevalent when using third party camera apps like those intended to film youtube videos or manipulate photos with instagram filters. Try opening your phone’s default camera app (Apple calls this “Camera”) and see if an image shows up there. Be sure to toggle the front camera/back camera button if you are experiencing an issue with just one of the cameras, as this may help turn on a camera that is having trouble.

Other apps putting a strain on your phone’s hardware can also prevent your camera app from showing an image. If you have tons of apps open and running on your phone, try putting all your apps to sleep before opening the camera app. To close background applications:

1. Swipe up from the bottom of the screen while on the home screen.
2. Hold your finger in the center of the screen to open the app manager.
3. Swipe the app up and off the screen to close it.
4. Repeat for each app that’s currently open until no apps remain.
5. Return to the home screen and open the camera app to check if your problem has been fixed.

If your screen is still showing nothing from the camera, try restarting your phone to reset the camera app. You can restart your phone by following these steps:

1. Hold the right-side button along with either the volume up or volume down button until the “Slide to Power Off” prompt appears on the screen.
2. Slide the slider across the screen.
3. Once the phone has finished powering down, hold the right-side button until the Apple logo appears.

It may sound silly, but it’s possible that your camera isn’t showing an image because it’s being blocked by something. Make sure that you aren’t covering your camera’s lens with any objects—like your fingers or a phone case. Most phone cases have cutouts for the iPhone 12’s camera placements, but it’s possible that the case is upside down, or a component of the case is blocking your camera’s view.

If you’re seeing an image but it isn’t clear, you may just have some dirt or grime sitting on your camera lens. Inspect the lens for any visible smudging before wiping the lens clean with a microfiber cloth. Once the lens has been cleaned, try using your camera again to see if your blurry images just got clearer.

While you may have ruled out an issue with the software responsible for displaying the image the camera sees, it’s also possible that the problem is originating from the software responsible for operating the camera’s hardware. To rule out your phone’s operating system as the culprit, you should first be sure to update to the latest version of iOS. To update your phone’s software:

1. Open the Settings app.
2. Navigate to the General settings tab.
3. From the general settings tab, navigate to the Software Update menu.
4. Select either the Download and Install or Install Now option from the menu.

Your phone may restart after the updates have been installed. Once you’re running the latest version of iOS, you can try a few additional things to rule out some of the more frequent software glitches affecting the camera.

One of these common software glitches occurs because of the Voice-Over feature on the phone. To shut it off:

1. Open the Settings app.
2. Navigate to the Accessibility settings tab.
3. From the accessibility settings tab, navigate to the VoiceOver menu.
4. Toggle the VoiceOver option to off.

Another common software glitch is that the flash becomes desynchronized from the camera module, which can cause an error that shuts down the entire module. To fix it:

1. Swipe down from the upper right-hand corner where the battery status icon is located to open the Control Center.
2. Press the Flashlight icon to turn on the flashlight.
3. Press the right-hand button to put the screen to sleep, leaving the flashlight activated.
4. Wait 30 seconds.
5. Turn the screen back on and use the Control Center to turn the Flashlight off.

Once you’ve done all this, open the camera app and see if your problem has been resolved.

If your camera continues to show a black screen and you don’t suspect the camera to be physically damaged by impact or water infiltration, your last result for a software fix is to perform a DFU (Device Firmware Update) reset. However, be aware that this may clear some or all data currently on your phone, so you’ll want to perform a backup to avoid losing precious data. To enter DFU mode on your phone:

1. Backup your phone.
2. Plug your phone into a computer with the latest version of iTunes downloaded using the USB to Lightning cable.
3. Press and immediately release the volume up button.
4. Press and immediately release the volume down button.
5. Press and hold the power button until the screen turns black.
6. As soon as the screen turns black, press and hold the volume down button, continuing to hold down the power button. Count to 5.
7. Once 5 seconds have passed, release the power button but continue holding the volume down button. Count to 10. The screen should remain black.
8. You can now release the volume down button. If performed correctly a prompt should appear on your computer screen saying: “iTunes has detected an iPhone in recovery mode. You must restore this iPhone before it can be used with iTunes.”
9. From here, follow the prompts on your computer to select and install the desired version of iOS for your device.
10. Exit DFU mode by performing a force restart on your phone.

If you’ve followed all of the above steps and your camera still doesn’t work, you can confidently rule out software issues as the culprit for your camera woes.

If your phone sustained a recent impact, if the back glass of your phone was shattered, or if you’ve been mounting your phone to your motorcycle, the camera module may have been physically damaged and will need to be replaced. Depending on the condition of your phone, you may be able to get Apple to fix the issue, but your luck may vary. Luckily, the fix is totally doable by the average user, so pull out the screwdrivers and get ready for the guide link.

If you’re ready to replace the camera yourself, you can do so by following our iPhone 12 Rear-Facing Cameras Replacement guide.