iPhone 15 Pro Overheating on Fast Charge: 17.0.3 Fix

You plugged your iPhone 15 Pro into a 20W or 30W brick, it started fast charging, and ten minutes later the back of the phone is hot enough that you don't want to hold it. You're on iOS 17.0.3. Battery Health still says 100%. The screen might dim without you touching anything, or you get the yellow thermometer warning.

Here's what's actually happening: iOS 17.0.3 changed the thermal management curve for the A17 Pro. Apple pushed it to fix the launch overheating complaints, and for a lot of people it worked. For some, it traded idle heat for charging heat. The phone now runs the CPU harder during the initial fast-charge handshake, and if any part of your charging chain is off, the heat stacks up fast.

Work through these in order. Stop as soon as your phone stays cool.

Fix 1: The 30-Second Test — Swap the Cable

This is the one people skip because "the cable works fine." Working fine and charging cool are two different things.

Unplug the cable from both the iPhone and the power brick.
Look at the USB-C connector on the cable. If it's a third-party braided cable you bought off Amazon for $9, that's your prime suspect. Cheap cables have higher resistance, and resistance turns into heat right at the connector.
Grab the cable that came in the iPhone 15 Pro box, or a known-good Apple USB-C cable.
Plug into the same brick. Start a charge. Set a timer for 10 minutes.
After 10 minutes, touch the connector at the bottom of the phone and the brick itself.

What you should see: the phone is warm — maybe 95–100°F on the back — but you can hold it comfortably. The connector isn't hot to the touch. If it still gets scorching with the Apple cable, move on.

The real fix here is almost always the cable. If you're using a random USB-C cable from an Android phone or a gas-station charger, replace it. Don't overthink it.

Fix 2: The 5-Minute Fix — Kill the Heat Sources Behind the Charge

An iPhone on a 27W charger is already dissipating roughly 4–6 watts of waste heat. Anything else running on top of that pushes it over the edge.

Open Settings > Battery and scroll down to Battery Health & Charging.
Tap Charging Optimization. Make sure Optimized Battery Charging is on.
Turn on Clean Energy Charging only if you're in the US and you charge overnight. If you fast-charge during the day, leave it off — it adds decision overhead with no thermal benefit.
Go back one screen. Tap Charging in the graph, then look at what apps were active during the last charge session.
If you see Photos, iCloud Backup, or any game in that list, that's your heat source. Plugging in triggers background sync because iOS assumes you're stationary.

Now the actual fix: before you plug in, do this.

Close every app. Swipe up from the bottom and flick them all away. Yes, all of them. iOS doesn't "need" them cached, and background refresh on 20 apps is real CPU work.
Turn off Bluetooth and Wi-Fi if you don't need them. AirDrop handshakes and Wi-Fi scanning both add load.
Turn the screen off. Don't scroll TikTok while it's charging. That's the single biggest thing most people do wrong.
Take the case off if it's a thick MagSafe case. A 2mm layer of rubber over a 105°F phone is a blanket.

Your phone should now charge to 50% in about 30 minutes with the back staying under 100°F. If it hits the thermometer warning again, go to Fix 3.

Fix 3: The 15-Minute Fix — Reset the Thermal and Power Stack

At this point you've ruled out hardware. The problem is likely a corrupted power management state that survived the 17.0.3 update. Here's how to clear it.

Step 1: Force restart (2 minutes)

Press and quickly release Volume Up.
Press and quickly release Volume Down.
Press and hold the side button until you see the Apple logo, then let go.

You should see the lock screen after about 20 seconds. Don't skip this because "I already restarted." A force restart is different — it clears the power management IC state, where a normal restart doesn't.

Step 2: Drain and recalibrate (overnight, but the setup is 5 minutes)

This is the one Apple Support won't tell you to do, but every technician I've trained does it for thermal complaints.

Use the phone until it shuts itself off. Not 1% — actually dead.
Leave it off for 2 hours. Don't plug it in.
Plug into a 5W charger — the old slow brick, not your 30W. Charge to 100% while the phone is off.
Once it hits 100%, unplug and turn it on.
Plug back into your normal charger and watch the temperature.

What you should see: the phone charges normally with the back staying lukewarm. If it's still hot, the battery management controller is misreporting cell voltage, and no amount of resetting fixes that.

Step 3: Check the thermal state directly

If you have a Mac with Console.app or Xcode installed, you can read the actual thermal state. Plug your iPhone in over USB, select the device in Console, and filter for thermal.

log stream --predicate 'subsystem == "com.apple.thermalmonitord"' --device

You'll see lines like thermalState: nominal or thermalState: serious. If it flips to serious within 5 minutes of starting a fast charge, the hardware is genuinely getting hot, not just reporting hot. If it stays nominal while your hand says otherwise, you have a sensor issue.

Step 4: Reinstall iOS 17.0.3 clean (last resort)

Take a full encrypted backup to your Mac or PC first. Then restore the phone in DFU mode and set it up as new — not from backup. This is the only way to rule out leftover state from a bad OTA update. Most people won't need this. If you do, and the phone still overheats on a 20W charger with a good cable and no apps running, it's a hardware problem.

When It's Actually Apple's Problem

If you pass all of the above and the phone still hits 110°F+ on a 20W charge with the original cable, screen off, no case, and nothing syncing, book a Genius Bar appointment. Apple has replaced batteries and, in a small number of cases, whole iPhone 15 Pro units for this. Bring your charger and cable with you so they can reproduce it in the store. Don't let them hand you a new cable and send you home — make them observe the temperature rise on the diagnostic bench.

One more thing: iOS 17.1 and 17.2 both included additional thermal tuning for the A17 Pro. If you're still on 17.0.3 and you've done everything above, updating is worth trying before you drive to the Apple Store.