Here are 12 of the most useful iPhone secret codes and what you can unlock with each one:

1. Display IMEI Number (*#06#)

The IMEI (International Mobile Equipment Identity) number is like your iPhone’s serial number. It’s a 15-digit code that uniquely identifies your specific device.

To view your IMEI number using the secret code:

  1. Open the Phone app and dial *#06#
  2. Tap the call button to execute the code.
  3. A popup will appear showing your iPhone’s IMEI number.

Knowing your IMEI number is useful for tracking down a lost or stolen iPhone. You can also use it for warranty claims or verifying your device information.

2. SIM Lock Status (*# ACCOUNT NUMBER#)

This code lets you check if your iPhone is network locked or unlocked. A locked iPhone will only work with the SIM card from a specific carrier. Unlocked means it can work with any carrier.

To check the status:

  1. Open the Phone app and enter # followed by your phone number and #. For example: #8675309#.
  2. Press call to execute.
  3. A message will appear showing your iPhone’s SIM lock status.

If your iPhone is locked when you want to switch carriers, this code verifies that before getting a new SIM.

3. Activate Field Test Mode (3001#12345#)

Field test mode enables advanced technical displays and analytics for troubleshooting network and cellular issues. It can provide detailed information about your connection and coverage.

To activate it:

  1. Open the Phone app and enter 3001#12345#.
  2. Press call to execute.
  3. Your iPhone will open the Field Test app with a technical overlay on the status bar for monitoring data.

You can tap various fields in the app to cycle between diagnostic data screens. To exit Field Test mode, just reopen the Phone app and enter the code again.

4. Carrier Settings Update (#UPDATE#)

This code will initiate a carrier settings update check if one is available for your iPhone. Carrier updates provide network, configuration, and feature improvements.

To run the check:

  1. Open the Phone app and enter #UPDATE#
  2. Tap the call button.
  3. If an update is available, your iPhone will download and install it automatically.

The update happens in the background, so just let it complete. Your iPhone will notify you when finished.

5. Display Battery Cycle Count (*#0228#)

The battery cycle count shows how many times your iPhone’s battery has gone through a full discharge and recharge. Knowing this can help determine when a battery might need replaced based on age and usage.

Here’s how to view it:

  1. Open the Phone app and enter *#0228#
  2. Tap call.
  3. A message will appear showing your iPhone’s battery cycle count number.

A typical iPhone battery lasts between 400-500 cycles before needing replacement. The cycle count can help you gauge your battery health.

6. Run Diagnostics Test (#0#)

This simple code initiates an iPhone diagnostics test to check all main systems and functions. It can uncover potential hardware or software issues causing problems.

To run a diagnostics test:

  1. Open the Phone app and dial #0#
  2. Tap the call button.
  3. Your iPhone will start a full diagnostic sequence, testing the display, cameras, sensors, radios, speakers, microphone, and more.

Let the test run through the various stages until it completes. If any issue is detected, your iPhone will display an error code that you can research for a solution.

7. Displayfirmware Version (*#ORIGINAL_IMEI#)

You can use this code to look up your iPhone's firmware version if you can't find it in the Settings app. Just enter your device's original IMEI number in place of ORIGINAL_IMEI.

This will display a screen showing your model identifier and firmware version. Knowing your exact iOS firmware version is helpful when troubleshooting issues or determining compatibility.

8. Check Voicemail Status (#50057672#)

Use this code to check your iPhone's voicemail configuration status. It will display if voicemail is activated and the assigned phone number.

  1. Dial #50057672#
  2. Tap call.
  3. A popup displays your voicemail status and number (if set up).

This returns useful information if you're having issues receiving voicemails on your iPhone.

9. Override Region Locks (*#0049#)

Entering *#0049# into your phone app overrides regional restrictions and country locks. This code can be useful when traveling internationally or using a foreign iPhone.

  1. Open the Phone app and enter *#0049#
  2. Tap the call button.
  3. Your iPhone will reset the country code selection.

This allows you to use a locked iPhone with a different SIM card outside its intended region or country.

10. Perform Soft Reset (*#7780#)

A soft reset can help resolve problems with frozen screens or apps. It resets settings and clears temporary files without erasing data.

To do a soft reset:

  1. Open the Phone app and enter *#7780#.
  2. Tap call to execute.
  3. Your iPhone will perform the reset process. Wait for it to complete.

This can restore normal operation if your iPhone is acting buggy or unresponsive.

11. Check NAND Flash Memory Usage (*#45377#)

This code displays your iPhone's NAND flash memory usage for troubleshooting or diagnostic purposes.

  1. Enter *#45377# into the Phone app.
  2. Tap call.
  3. A page will appear showing used and available NAND flash memory.

Monitoring this over time can reveal potential issues if space becomes too low.

12. Access Hidden Field Test Menu (3001#12345# or *#5346#)

Both of these codes open a hidden Field Test menu with advanced cellular, network, location, and coverage data. You can use it to monitor and troubleshoot connection issues.

To access the hidden menus:

  1. Enter either 3001#12345# or *#5346# into the Phone app.
  2. Tap call.
  3. Your iPhone will open the Field Test app with technical data.

Navigate through the various screens using the side arrows and back button. Tap fields to cycle between data sets. To exit, reopen the Phone app and re-enter the code.