As the most popular phone brand, the iPhone boasts many unique features. However, it can also malfunction, and random restarts are one such issue. To prevent this from impacting your daily life, this article analyzes common causes of iPhone restarts and shares practical solutions.
Common causes of iPhone restart problems
Although the iPhone adopts a closed ecosystem and is more stable than most Android devices, it still experiences reboot failures, and the core reasons are mainly divided into four categories:
1. Software failures and update exceptions
iOS is at the heart of your iPhone's operation, and even minor software vulnerabilities can trigger a restart. For example, when updating iOS, the power suddenly loses, resulting in incomplete update files; or the old version of the app is not compatible with the latest iOS , which conflicts with the system, causing the phone to restart frequently. In addition, accidentally deleting key system files can also disrupt system stability and trigger automatic restart.
2. Battery aging and hardware failure
The lithium-ion battery in the iPhone usually drops significantly after 500 charge cycles. The aging battery cannot provide stable power supply, and when the phone runs power-hungry tasks, the voltage drops sharply, and it will be forced to restart. At the hardware level, a loose charging interface, a malfunctioning power button, and a faulty logical motherboard can also cause unexpected reboots.
3. Overheating triggers thermal protection mechanisms
iPhone is designed to operate in a temperature range of 0°C-35°C, and if you use it in direct sunlight for a long time, continuously record 4K video or play AR games, or wear a thick, breathable case, the temperature of the device will exceed the safe range. In order to avoid hardware burnout, the system will activate the thermal protection mechanism and force the phone to restart, which is a safety warning and needs to deal with overheating problems in time.
4. Malware and system file corruption
Although iPhones are highly secure, downloading apps from uncertified third-party platforms and clicking on suspicious email links can still infect you with malware. These malicious programs can tamper with and damage system files, such as corrupting kernel running files, which may cause the phone to crash and restart when opening Settings.
How to fix iPhone restart issues
Once the potential cause is found, you can repair it according to the following steps, each step with corresponding repair tools, which can not only accurately locate the problem, but also avoid damage to the equipment due to operational errors:
Tips：If the iPhone only restarts while charging, there is a high probability that the charging interface or power supply is abnormal, you can use the charging port tester to quickly detect it first.
1. Plug the Lightning connector of the Phone Charging Port Tester into the iPhone charging port, connect the original Apple charger to the other end, and turn on the tester switch.
2. Observe the tester display: If the voltage display is stable at 5V or 9V, and the current does not fluctuate frequently, it means that the power supply to the charging port is normal; If the voltage rises and falls, the current is displayed as 0, or an error is reported, it indicates that the charging port has problems such as poor contact and damaged internal pins, and further disassembly and maintenance are required.
3. If the tester prompts "interface short circuit", the power supply should be disconnected immediately to avoid damage to the motherboard caused by a short circuit.
Detect battery health
When you suspect a battery problem, in addition to checking the "battery health" data in the system, you can also use the Digital Multimeter to check the actual battery power supply, the steps are as follows:
1. First go to "Settings"> "Battery" > "Battery Health and Charging", if the "maximum capacity" is less than 80%, the battery is preliminarily judged; If the capacity is normal but still restarts frequently, it is necessary to disassemble the machine to test the battery power supply.
2. After disassembling the machine according to the specifications (unscrewing the bottom screw with a precision screwdriver and separating the screen with a plastic crowbar), find the battery cable connector, adjust the universal meter to "DC Voltage Level (DCV)", and select the range of 10V.
3. Use the red meter pen of the universal meter to lightly touch the positive contacts of the battery cable, and the black meter pen to touch the negative contacts (be careful not to touch both contacts at the same time to avoid short circuit), and the voltage should be stable between 3.7V-4.2V under normal circumstances; If the voltage is lower than 3.5V or fluctuates more than 0.3V, the battery power supply is unstable and needs to be replaced with a new battery.
Replace the aging battery
After confirming the aging of the iPhone Battery, replace it with a precision screwdriver set, as follows:
1. Use the five-star screwdriver in the set to align the screws on both sides of the charging port on the bottom of the iPhone, unscrew them slowly counterclockwise (with even force to prevent the screws from slipping), pick up the screws with tweezers, and put them in the parts box for storage.
2. Take the plastic crowbar, insert it through the screen gap near the charging port, gently pry it up until a small gap appears, and then slide the crowbar along the edge of the fuselage to gradually separate the screen (there is a cable connection at the top of the screen, which cannot be completely lifted).
3. Use anti-static tweezers to remove the protective cover of the battery cable connector, and then gently pick up the cable to disconnect the battery from the iPhone motherboard , the anti-static design can avoid hand static damage to the motherboard, and the slender head of the tweezers can accurately operate the small connector to prevent accidental contact with other components.
4. Remove the old battery, install the new battery, and reset it in the opposite step: first connect the cables, cover the protective cover, then fit the screen, and finally screw back the bottom screw with a screwdriver to complete the replacement.
Check the internal hardware connections
If the battery is still restarted after replacement, check the connection between the internal cable and the components, and the tool usage is as follows:
1. After disassembling the machine, gently clean the dust on the surface of the motherboard and cable connectors with a Soft Bristle Brush (keep the power off when brushing, and use gentle force to avoid dust entering the gaps of the components), the accumulation of dust may lead to poor contact with the wiring and cause unstable power supply.
2. Focus on checking the connectors of the charging port cable and the power button cable: if the connector is found to be loose, use anti-static tweezers to press down vertically to ensure close contact; If the connector is stuck to the motherboard (due to long-term use), adjust the Hot Air Gun to 80-100°C low temperature setting, 10-15 cm away from the connector and heat it slightly for 3-5 seconds, and after the adhesive softens, use a plastic crowbar to gently pick up the cable to avoid hard breakage and damage.
3. After the inspection is completed, clean the interface again with a soft brush to ensure that there are no impurities remaining, and then reset the cable and screen to test whether the phone is back to normal.
Troubleshooting tips for iPhone restart issues
If the above methods don't work, you can further locate the problem with the following tips, the details of which are assisted by the tools are as follows:
1.Water Damage Investigation: Check the water intrusion detection sticker in the SIM card tray, if the sticker turns red, immediately turn off the power and use a soft cloth to absorb the surface moisture. During professional maintenance, the technician will use a heat gun to dry the internal moisture at low temperature, and then use a multimeter to detect the element on or off to avoid water diffusion caused by self-operation.
2.Charger and data cable test: Use the charging port tester to connect different original chargers and data cables, if only one set of accessories triggers the restart, it means that the accessories are faulty and need to be replaced; If all accessories are abnormal, you still need to focus on the internal hardware maintenance of the phone.
3.Official diagnosis cooperation: Remote diagnosis is initiated through the "Apple Support" APP, if the hardware failure is prompted, you can take the device to a professional repair point, and the technician will use special testing equipment combined with tools such as multimeters and heat guns to accurately locate problems with core components such as logic motherboards.
Conclusion
Most iPhone restart issues can be resolved through tool-assisted testing and step-by-step troubleshooting. Using professional tools and following standard procedures can completely eliminate the annoyance of frequent restarts. If you're looking for trusted repair tools, Phonefix offers a full range of high-quality repair tools and welcomes your inquiry at any time.
