iPhone Duo Troubleshooting Cellular Issues

Guided steps to help resolve issues

Identify issues

Read the relevant support articles if you notice any of the following issues:

• Calls disconnect

• Can’t make or receive calls

• Can’t send or receive text messages

• Can’t use cellular data for apps such as Maps, Weather, or Stocks

• No cellular signal indicators

• “No Service” or “Searching” message

• No cellular connection for calls

• Signal strength is always very weak

• Weak or slow cellular connection

• Poor, low, or distorted sound during calls

• eSIM or nano-SIM setup and activation issues

• “Invalid SIM” or “No SIM Card Installed” message

• Locked nano-SIM

Relevant support articles

• About cellular data roaming options for your iPhone and iPad

• Connect to a satellite with your iPhone

• Find wireless carriers and worldwide service providers that offer eSIM service on iPhone

• If Personal Hotspot is not working on your iPhone or iPad (Wi-Fi + Cellular)

• If you can’t activate your iPhone or iPad (Wi-Fi + Cellular)

• If you can’t make or receive a FaceTime call on your iPhone or iPad

• If you can’t send or receive messages on your iPhone or iPad

• If you can’t turn on or sign in to iMessage or FaceTime on your iPhone

• If you see a Cellular, Ultra Wideband, or Apple Pay issue

• If you see SOS, No Service, or Searching on your iPhone or iPad

• If your device has network connectivity issues, check for VPN and other third-party security software

• Learn which type SIM card your iPhone or iPad uses

• Make a call with Wi-Fi Calling

• Set up eSIM on iPhone

• Learn the meaning of iPhone status icons

• Use 5G with your iPhone

• Use cellular data on your iPhone or iPad

• Use eSIM while traveling internationally with your iPhone

• Use Messages on your iPhone or iPad

• Using Dual SIM with an eSIM

• View and edit your APN on your iPhone and iPad

If the issue wasn’t resolved by following a support article, continue to the next section.

Try quick troubleshooting steps

1. If the device appears to be connected to the internet but can’t access the web, download content, or make other connections as expected, check VPN or other third-party security software on the device. Some software, including VPN apps or configuration profiles, may have settings or restrictions that can cause connectivity issues. This software may need to be deleted or disabled to resolve the connectivity issue. If you do so, use caution: deleting an app or changing a configuration profile could affect how the device can be used. Follow recommended steps in If your device has network connectivity issues, check for VPN and other third-party security software for more information and instructions.

2. Refer to If you see SOS, No Service, or Searching on your iPhone or iPad to verify device and cellular network compatibility.

Run manual and diagnostic tests

If the issue wasn’t resolved by following a support article or trying the quick troubleshooting steps, run these diagnostic and manual tests to help isolate the cause of the issue:

1. For eSIM issues, go to Settings > General > About and verify that the following information is present:

   • eSIM Network: network name

   • EID: 32-digit number

     • The presence of an EID number indicates that the eSIM is functioning correctly. If no number is present, the eSIM isn’t functioning correctly.

   • IMEI: numerical code

   • ICCID: numerical code

2. Run the Mobile Resource Inspector (MRI) diagnostic suite.

3. Go to Settings > General > About. Check whether the Modem Firmware section is blank. If so, the cellular connection might not be functioning correctly.

4. Go to Settings > General > About. Check whether the EID section is blank. If so, it could indicate an issue with the eSIM.

5. Go to Settings > General > Transfer or Reset iPhone. Then tap Reset and select Reset Network Settings.

6. Caution: Resetting network settings will erase all stored Wi-Fi passwords.

7. Run the Audio diagnostic suite. Check diagnostic results to determine whether the issue is audio related. If so, review Sound issues.

8. Go to Settings > General > Transfer or Reset iPhone. Then tap Erase All Content and Settings and select Erase All & Keep Data Plans, which will preserve the eSIM. Retest for cellular connectivity functionality.

   • Important: If the eSIM is erased during troubleshooting, you’ll need to obtain a new eSIM to reactivate cellular service. Erasing all content and settings will delete all user data on the device.

Open and inspect the iPhone

If the issue wasn’t resolved or isolated by following support articles or running diagnostic tests, refer to the iPhone repair manual to open and inspect the iPhone. A damaged or out-of-place part may be causing one of the issues.

1. Inspect all relevant internal flex cables and connectors for damage or tampering, such as a film or foreign material blocking a connector.

Note: This section requires ordering parts and tools. Replacing a part may not resolve the device’s issue. You can find other service options at support.apple.com/repair.

Replace the part

If the issue wasn’t resolved or isolated by following the previous steps, replace the logic board or I/O board, depending on diagnostic results.

After the repair is completed, turn on the device and verify that the issue is resolved.

Note: This section requires ordering parts and tools. Replacing a part may not resolve the device’s issue. You can find other service options at support.apple.com/repair.

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