iPhone 15 Problems: Bluetooth, Battery, Overheating & Fixes

Five minutes into the drive, the call jumps from the car speakers back to the phone in the cup holder. That’s the iPhone 15 complaint that refuses to go away, and it heads the list of iPhone 15 problems we see from owners three years after launch. The rest are familiar: drain after a big iOS update, heat on the charger, and a USB-C port that suddenly won’t charge.

Start with two things that clear a surprising number of glitches. Install the latest update in Settings › General › Software Update, then force restart: press and release volume up, press and release volume down, and hold the side button until the Apple logo appears.

Car Bluetooth drops calls and music

Bluetooth is the longest-running iPhone 15 issue. According to Tom’s Guide and TechRadar, owners were still reporting it almost six months after launch: calls dropping after a few minutes, music cutting out, and the car disconnecting so often that calls fell back to the phone’s own speaker. Several reports involved older cars, BMW and Audi models from around 2011 to 2014, that had worked fine with earlier iPhones. Some owners also had trouble with AirPods and Beats headphones.

What it usually looks like:

• The phone connects, then drops after 5 to 10 minutes.
• Calls move from the car to the iPhone mid-conversation.
• The car says the phone is connected, but no audio plays.

Work through these, simplest first:

1. Turn Bluetooth off and on in Settings › Bluetooth. Control Center only disconnects accessories, so it doesn’t count.
2. Forget the pairing on both ends. In Settings › Bluetooth tap the i next to the car and choose Forget This Device, then delete the phone from the car’s list as well, and pair again from scratch.
3. Clear out old phones from the car. Many head units hold a limited number and misbehave when the list is full.
4. Update the car’s infotainment firmware through the manufacturer’s app or the dealer. Older units often get Bluetooth compatibility fixes.
5. Reset network settings in Settings › General › Transfer or Reset iPhone › Reset › Reset Network Settings. This wipes saved Wi-Fi passwords too.
6. Try a different Bluetooth device. If headphones and speakers drop as well, book an Apple diagnostic, because a fault that hits every accessory can be hardware.

The USB-C port stops charging

The iPhone 15 was the first to swap Lightning for USB-C, and a lot of “not charging” cases turn out to be pocket lint packed into the port so the cable can’t seat fully.

1. Shine a torch into the port. If you see lint, switch the phone off and ease it out with a wooden or plastic toothpick. Never use a metal pin, and don’t blast compressed air deep inside.
2. Try another cable and charger. For fast charging you want a USB-C Power Delivery charger rated 20W or more. Cheap cables and low-power adapters may charge very slowly or not at all.
3. If iOS says liquid was detected, unplug and let it dry. Don’t charge until the warning clears. Our water damage check explains the other signs.
4. Put it on a MagSafe or Qi pad. If wireless works and USB-C doesn’t, the port or its board connection is probably damaged, which means a repair.
5. Force restart while it’s plugged in to rule out a software hang.

Hot while charging: normal or not?

At launch the overheating headlines were about the Pro models. Gulf News, citing Bloomberg, reported iPhone 15 Pro and Pro Max owners saying their phones got “too hot” while gaming, on FaceTime or while charging. Apple later blamed an iOS 17 bug and some third-party apps and fixed it in iOS 17.0.3. Some base iPhone 15 owners noticed warmth too, mostly on the charger.

Some heat is expected on the first day after setup or an iCloud restore, during fast charging (especially if you’re using the phone), while gaming, navigating, recording video or running a hotspot, and in direct sun or on a hot dashboard.

To bring it down, take thick cases off while charging and put the phone on a hard surface, not a bed or sofa. Stop using it while it fast-charges if it feels very hot. Update your apps, since heat bugs are often fixed in app updates. If the temperature warning screen appears, let it cool before you carry on. Repeated warnings in a normal room deserve an Apple diagnostic.

Battery drain after the iOS 27 update

Every big release brings drain complaints, and Cybernews collected reports of “higher battery drain than before” after iOS 27, iPhone 15-series owners among them. Most of the time it’s temporary. After a major update the iPhone re-indexes photos, messages and search data in the background, which can take a few days. The wider bugs are tracked in our iOS 27 problems and fixes page.

1. Give it two or three nights on charge and on Wi-Fi so indexing can finish.
2. Look at Settings › Battery. Update or offload any app with unusually high background activity.
3. Rein in background work in Settings › General › Background App Refresh (Wi-Fi only, or off, for apps you don’t need) and review Location Services in Settings › Privacy & Security.
4. Open Settings › Battery › Battery Health. Apple designs iPhone 15 and later batteries to keep up to 80% capacity after 1,000 full cycles under ideal conditions. A phone near or under 80% drains faster on any iOS version.
5. Still bad after a week? Back up, erase and restore. A corrupted setting carried across updates can keep the drain going.

One feature worth switching on: the iPhone 15 was the first base model with a charge limit. In Settings › Battery › Charging you can cap it at 80% (or higher steps), which cuts long-term wear if a charger is usually nearby. More on that in our battery health and parts history explainer.

Ghost images, tint and dead spots on the screen

The iPhone 15 has an OLED display, and OLED can show image retention, a faint ghost of a keyboard or navigation bar, if the same bright image sits on screen for long periods. Reports on the iPhone 15 are uncommon and Apple uses software to reduce the risk. On an older, hard-used phone, though, it helps to keep Auto-Brightness on (Settings › Accessibility › Display & Text Size), set a short Auto-Lock in Settings › Display & Brightness › Auto-Lock, and avoid leaving navigation or a static app at full brightness for hours.

Touch dead zones, a colour tint or flicker on a used phone more often mean a non-genuine replacement screen. Settings › General › About › Parts and Service History shows whether the display, battery or camera has been replaced and whether the part is genuine Apple. Our page on checking for original parts goes further.

When to book Apple instead of trying another fix

Take it to Apple Support, an Apple Store or an Apple Authorized Service Provider if:

• Bluetooth fails with every accessory even after a network reset and an erase.
• USB-C won’t charge with cables you know are good, but wireless charging works.
• Battery Health shows Service, or capacity is close to 80%.
• The display has lines, dead zones or a tint that doesn’t go away.

The iPhone 15 came out in September 2023, so Apple’s one-year limited warranty has run out on most units. AppleCare+ may still cover yours. An iPhone warranty check tells you before you pay for anything.

Buying a used iPhone 15: what to check

It’s a good second-hand buy, but some listings hide a tired battery, a swapped screen or an iCloud lock. Before you pay:

1. Dial *#06# or open Settings › General › About for the IMEI and serial number.
2. Run the free All-in-one Basic Info check to confirm the model and Find My status.
3. Get a full Apple GSX report for warranty, purchase country and repair history.
4. Check the GSMA blacklist so you don’t end up with a phone reported lost or stolen.
5. In person, pair it with your car or headphones, charge it with your own cable, and look at Battery Health and Parts and Service History.

Still choosing between generations? Our used iPhone model guide puts the iPhone 15 next to the newer models.