A quick-reference of every iPhone/iTunes error code — what it means and what to do.
Key: ● Hardware · ● Software · ● Network/USB
Hardware errors ●
-1: Baseband chip failure. Blank IMEI = confirmed.
1: Can't downgrade or old iTunes.
3: NAND or baseband fault.
9: USB disconnect. Cable/port/internal.
16: Baseband IC dead (water damage).
23: Baseband comm error (water damage).
28: Charging port damage.
29: Battery problem.
40: Internal component comm failure.
53: Touch ID damaged/replaced.
56: Touch ID/Face ID mismatch.
4005: USB dropped during restore.
4013: Most common. USB/NAND/Audio IC.
4014: Same as 4013.
Network errors ●
17: Can't reach Apple servers.
1638: Server timeout.
3000: No internet.
3004: Firewall blocking Apple.
3014: Server overloaded.
3194: hosts file blocking. Remove gs.apple.com.
3200: Incomplete IPSW download.
USB errors ●
1601: USB comm failure.
1602: Driver issue. Reinstall iTunes.
1611: Recovery Mode failure. Use DFU.
2001-2011: USB chipset. Remove hubs.
Software errors ●
2: iTunes install failed (Windows).
4: Security software blocking.
6: Can't enter Recovery Mode.
14: Corrupted IPSW. Re-download.
1015: Unsigned iOS. Use latest.
1110: Not enough storage.
1671: Still downloading. Wait.
4037: Device locked. Enter passcode.
Alerts
SOS Only / No Service: SIM/carrier/antenna/baseband.
Cellular Update Failed: Check Settings → About.
Apple Pay Requires Update: Go to Settings → About.
If none of the above works, the issue is most likely physical hardware damage — a failing chip, corroded connector, or broken internal component. If you've tried everything above and the error keeps coming back, the problem is most likely physical — something broken inside the device that software can't fix. That's when it needs professional hands-on inspection.