iPhone Troubleshooting Guide for Commonly Used iPhone Problems and How to Fix Them

iPhone troubleshooting is an important skill for device resellers who want to maximize their profits. iPhones with defects are relatively inexpensive to get, and once repaired, have high resale value. Learning how to troubleshoot iPhones is not as difficult as many think.

Why Knowing How to Troubleshoot iPhone Problems Matters

While many resellers focus on buying fully functional devices, they may miss out on a valuable opportunity: pre-owned iPhones with minor, fixable issues.

Wholesalers who understand how to diagnose and resolve common iPhone problems can maintain higher device quality, reduce return rates, and build stronger relationships with retail partners. At WeSellCellular, we support wholesalers by sourcing reliable inventory and helping them deliver consistent value with every transaction. By fixing and improving the quality of discounted devices, resellers can unlock even more profit while fostering long-term customer trust.

1. Battery Health and Rapid Drain Issues

Among things to check when buying used iPhones, the batteries top the list of common iPhone problems. iPhone batteries, like all lithium batteries, wear down with use. The older an iPhone is, the more likely the battery will fail.

Used iPhones generally have less battery capacity than new phones. However, some older iPhones can have rapid battery drain issues — where the battery goes from 80% down to 20% in a short time period — especially after certain iOS updates. Apple confirmed that iPhones with older batteries will slow themselves down.

The good news is that some known battery-drain issues related to software are addressed in later updates. Apple has also added battery-capacity monitoring. In some cases, upgrading a phone’s iOS can fix battery issues.

How to Fix Bad Batteries

As a first step, upgrade the phone’s iOS. If this doesn’t work, problems with iPhone batteries are best addressed by replacing the battery, which you can usually accomplish in minutes. And it gets easier each time you do it. Here’s a list of YouTube video tutorials for iPhone battery replacement to help you get started.

2. Touch ID and Face ID Not Responding

In some cases, used iPhones have issues with the Touch ID security feature. Much of the time, these issues are temporary and can be fixed with software updates. But, as with battery issues, this does not always work.

How to Fix Touch ID Problems

If you buy iPhones in bulk and come across devices with Touch ID issues, the first iPhone problem solution is to restore the system to its default settings. You can also try restarting the iPhone and verifying that the Touch ID feature is active. If that doesn’t work, update to the latest version of iOS and rescan a fingerprint.

Keep in mind that the Touch ID can be sensitive. Use a microfiber cloth to clean the Touch ID. This allows you to remove any dust or debris that otherwise causes the reader to malfunction.

A light touch of the Touch ID won’t register a response. When testing a Touch ID on a used iPhone, ensure your whole finger is pressed against the reader. You should keep your finger still for at least a few seconds to see if the reader responds to it.

The case or screen protector used for an iPhone can impact the Touch ID’s response as well. Be sure to remove the case or screen protector from an iPhone before you test a Touch ID.

How to Fix Face ID Problems

Face ID began replacing Touch ID as the primary user authentication protocol with the iPhone X in 2017. Like Touch ID, Face ID sometimes becomes unresponsive. A common failure scenario is for it to stop working after an iOS upgrade. If Face ID is properly set up and your face isn’t unlocking the iPhone, try rebooting the device. If that doesn’t fix the issue, enter Settings and reset Face ID.

3. Touch Screen and Display Sensitivity Problems

Touch Disease is a unique iPhone screen problem. This issue happens when the touch controller chip fails to fully connect to the logic board. The first symptom is a flickering gray bar that appears at the top of the display. As the chip detaches further, the phone’s touch screen becomes unresponsive.

This was the most common defect in the iPhone 6 and 6+. It also appears in later iPhone models.

How to Fix Touch Screen Problems

You may be able to fix Touch Disease with a simple force restart. Or, you can delete resource-intensive apps from your iPhone, restore the device’s factory settings, or remove and replace its SIM card. If none of these solutions work, you can microsolder the touch screen controller chip back onto the logic board. This requires precision and care. If you make a mistake as you microsolder, you risk permanent damage to the iPhone.

4. No Vibration or Weak Haptic Feedback

In terms of common iPhone problems, a lack of vibrations may rank near the top of the list. When there are no vibrations, your iPhone handset is not working properly. To correct the issue, your iPhone’s vibration motor may need to be replaced. Fortunately, replacing the vibration motor in a used iPhone is relatively simple.

Sometimes a handset will stop vibrating or providing haptic feedback after an iOS update. Yet the problem isn’t always caused by a software issue. When restoring factory settings or doing a DFU restore doesn’t fix the problem, chances are that the haptic engine is defective and needs to be replaced.

How to Fix No Vibrations

Go to your iPhone’s Accessibility settings to verify that the switch next to Vibration is on. If the switch is green, your device should vibrate.

It is also possible that an iPhone won’t vibrate if the device’s vibration pattern is set to None. In this instance, go to Settings and select General, followed by Sounds & Haptics, then Ringtone. At this point, select Vibration at the top of the screen. Ensure there is a checkmark next to everything other than None.

If neither of these tips work, your iPhone’s vibration motor may be defective. Here’s a step-by-step guide to replace a vibration motor in an iPhone.

5. Cracked Screen or Glass Replacement

An iPhone is a strong, sturdy device, with or without a case and screen protector. Regardless, accidents happen. If an iPhone gets dropped or falls, the screen can crack. Cracked glass is a common iPhone issue. The only way to correct this issue is to replace the entire screen.

How to Replace Cracked Glass

Kits are available online that you can use to replace a cracked iPhone screen. They often include instructions you can follow to safely remove a cracked iPhone screen and install a new one. For example, this video demonstrates how to replace the screen on an iPhone 7 Plus. There are other video tutorials on YouTube for DIY screen replacement for all iPhone models.

6. iPhone Overheating

Like most electronics, the iPhone has an ideal operating temperature range. iPhones are made to perform safely in temperatures from 32 to 95 degrees. iPhones can be pushed beyond their safe operating temperature by environmental conditions (such as a hot parked car) or user actions (i.e., playing a graphics-heavy game while charging). When an iPhone is overheated, a temperature warning may be displayed.

How to Fix iPhone Overheating

Understand the cause of the iPhone's overheating. Is it the hot conditions in the environment? If so, discontinue use and move to a cooler area, out of direct sunlight. Note that it’s never appropriate to place the iPhone in a freezer or refrigerator, as the sudden cooling can damage the device. If outside temperatures are normal and the iPhone is overheating, then usage may be the cause. Shut down any resource-intensive applications, turn off background updates, disable the auto-brightness setting, and set the screen brightness to a moderate setting. Then wait for the phone to cool naturally.

7. Wi-Fi or Bluetooth Connectivity Issues

One of the most important features of an iPhone is its data connection to the internet and other devices. If Wi-Fi and Bluetooth aren’t working, the functionality of the phone becomes limited as it’s unable to access the internet or play audio using Bluetooth. Fortunately, most connection issues can easily be resolved.

How to Fix Wi-Fi and Bluetooth Issues

The first troubleshooting tip for Wi-Fi is to “forget” the network and reconnect to it. This is achieved by navigating to the Wi-Fi networks screen, clicking the “i” icon next to the network and tapping “forget this network”. Then reconnect to the network.

If forgetting and reconnecting to the network didn’t work, try resetting the router. It’s possible the iPhone isn’t the issue at all, and the router is malfunctioning. If the router resets and you can connect to it on other devices but not the iPhone, then you’ve established that the iPhone is the source of the connection problems.

Next, try resetting the iPhone. If that doesn’t resolve the issue, reset your network settings. You can do this by navigating to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings.

8. iPhone Not Charging or Slow Charging

An iPhone that can’t be charged isn’t much use. To resolve this failure, it may be necessary to try different charging cables and power adapters. Sometimes the defect lies in the charging equipment and not the iPhone itself. If it charges but only very slowly, check that “Optimized Battery Charging” isn’t active.

How to Fix an iPhone Not Charging or Slow Charging

First, try to isolate the problem. Is it the iPhone, cable, power adapter or wall outlet that’s the issue? Try different combinations of cables, adapters, and outlets. If all the power accessories appear to be working and undamaged, it may be the iPhone that’s preventing power charging.

Examine the charging port for obstructions, and gently clean it. If you can power on the device, reset it. Next, reset all settings.

If that doesn’t work, try updating to the latest version of iOS. If none of these approaches are successful, it may be a hardware issue. Either the battery, charging port, or motherboard may need to be replaced.

9. Sound, Speaker, or Microphone Problems

The ability of the iPhone to produce clear sound is critical for calls, FaceTime, music, video, and gaming. If the iPhone is making distorted sounds or has no sound, it may be time to check your settings and clean the speaker. Likewise, the microphone should be cleaned if callers are having difficulty hearing you.

How to Fix Sound and Microphone Problems

The first step to resolving sound problems is checking settings. Be sure that the phone is not set to silent mode. If your iPhone has a silent mode switch, slide it towards the screen to disengage. Toggle up the volume to be sure that the volume is set to an audible level. Disable the “Do Not Disturb” mode by going to Settings > Focus > Do Not Disturb. If none of these setting changes produce sound, there may be a physical obstruction in your speaker. Remove the case and screen protector, and brush the speaker with a soft-bristle brush. If these fixes don’t work, you may need to replace the speaker unit.

10. iPhone Freezing or App Crashes

iPhones can become stuck or “frozen” in an unusable state. When this happens, a reset generally fixes the issue; however, sometimes the reset menu itself cannot be triggered. In that event, you can perform a “force restart”.

How to Fix iPhone Freezing

To conduct a “force restart,” follow this pattern of button presses:

• Press and release the volume up.

• Press and release the volume down.

• Press and hold the side button.

• When an Apple logo is displayed, let go of the side button.

If the iOS operating system is fine, but a specific app keeps crashing, try reinstalling the app. If the problem persists, contact the app developer for further assistance.

Tips for How to Fix iPhone Problems

You don’t need to be an Apple expert to know how to fix iPhone problems. Here are tips to help you troubleshoot common iPhone problems:

• Restart Your iPhone: Turn the iPhone off, then on. A reboot resets the iPhone’s software and can restore it to a stable state.

• Update the iOS: Ensure the operating system on the iPhone is up to date. An iOS update usually takes only a few minutes to download and can immediately improve a device’s speed and performance.

• Reset All Settings: Perform a factory reset to correct software and hardware problems.

• Review Your Battery’s Health: Take advantage of the battery health setting (available in iPhones running iOS 11.3 and later) to assess your device’s performance. If the battery’s performance has severely deteriorated, replace the battery.

• Clean Ports: Watch for debris that can build up inside your iPhone’s ports. Use a can of compressed air to remove debris from the ports.

These tips won’t resolve every Apple iPhone defect. But, they can help you quickly and affordably address common iPhone problems. You can also use them to continuously review the condition of iPhones in your inventory and prevent problems from cropping up.

How to Choose Reliable Used iPhones

The quality of your iPhone inventory depends on who you buy from. If you choose a reputable provider of accurately graded iPhones, you’re going to avoid many device issues altogether and minimize the time you spend on iPhone troubleshooting.

When purchasing smartphones in bulk, we encourage you to work with an industry-leading iPhone provider with a documented grading and review process. By carefully choosing your supplier, you can source iPhones that meet or exceed your expectations. Plus, you can likely avoid buying an iPhone with a charging problem or similar issues.

WeSellCellular has a rigorous 45-point grading system that evaluates functionality and cosmetics. When you purchase from WeSellCellular, you can be confident that our meticulously graded phones minimize risk for your business. Note that specific grading standards apply to purchases from WeSellCellular’s third-party partners; such orders use Supplier Direct grading.

While issues can surface when buying iPhones in bulk, many can be fixed with minimal effort. Just knowing how to interpret iPhone warning messages goes a long way. It’s up to you as a buyer to determine which grades you want to focus on. At the end of the day, it all comes down to price and value. In some cases, buying repair inventory can be more profitable than any other purchase, given that you get the right discount.

At WeSellCellular, we help companies buy iPhones in bulk. As anyone in the industry knows, every day in this business presents new challenges. Our goal is to help you prepare to deal with whatever issues come your way so that you can maximize your profits.

We encourage you to check out our iPhone bulk inventory today. You can explore a variety of quality iPhone models that can help you boost your revenues and differentiate yourself from rivals.

Final Thoughts on iPhone Troubleshooting and Maintenance

Used iPhones with known issues are sold at a steep discount, making them more affordable to acquire. By learning how to fix basic problems, resellers can increase their profit margins. Offering repairs also helps resellers stand out from those simply trading phones.

Regular maintenance can help prevent common issues. Establish a routine for cleaning iPhone ports, screens, and cases, and ensure that apps and operating systems are updated regularly. This proactive approach helps maintain device performance and reduce the need for repairs.

WeSellCellular has written guides on what to look for when buying wholesale phones and everything you need to know before buying iPhones. Already know the basics? Then it’s time to secure your inventory. Our stock of used iPhones is deep and comprehensive.

When evaluating a wholesale partner, the best way to make the choice is based on who has the best grading standards. To help you make that assessment, WeSellCellular has a guide to grading scales, too.

Create an account with WeSellCellular and start buying today.