Problems With SIM Cards in iPhonesby Erik Devaney
A subscriber identification module, or SIM, card is a removable memory chip that stores a cell phone user's account information. This information can include call logs, contact lists and sent and received text messages. While SIM cards can make upgrading to new phones and switching over to different phones simpler processes, the cards can also cause problems. This is especially relevant when it comes to Apple's line of iPhone smartphones, which have notoriously suffered from SIM card problems in the past.
"No SIM Installed"
In some instances, an iPhone may display the message "No SIM installed" after you turn the phone on. As long as this message appears, the iPhone will be unable to function. To remedy this problem, Apple recommends that you first remove the SIM card, which you can accomplish by pushing the end of a paper clip -- or a SIM ejector tool -- into the hole on the iPhone's SIM card tray. After the tray pops out and you remove the card, reinsert the card and tray and turn off the phone. When you turn the iPhone back on, it will, ideally, detect the SIM card within two minutes and the phone will function properly. If the iPhone is still unable to detect the SIM card, it may be because the SIM card is dirty or damaged.
Dirty or Damaged SIM Card
If an iPhone is able to recognize an alternative SIM card, but not the card that the phone came with, this is an indication that the original iPhone SIM card is dirty or damaged. To clean a dirty SIM card, you can lightly rub the card's gold contacts with a rubber eraser. Alternatively, you can clean the contacts with a specialized circuit-cleaning pen, which you can find at electronics stores. If a SIM card still does not function in an iPhone following cleaning, it is likely that the SIM card is damaged and requires replacement. Cracks and scratches on the SIM card are other, more visible indicators of damage.
Sending an iPhone in for Repair
If it turns out that an iPhone's SIM card is damaged or that an iPhone is unable to read a "healthy" SIM card, you will likely want to send that iPhone to Apple for repair work. Before sending in an iPhone, make backups of all your phone's data and then erase the phone's contents and settings. You can accomplish this by selecting Settings, then General, then Reset and finally, Erase All Content and Settings.
While some problems with SIM card in iPhones are not preventable, there are some preventive measures you can take to ensure that a SIM card does not become dirty or damaged. For example, you should always treat your iPhone delicately; do not toss it onto a table or surface and do not assume that a friend will catch it if you toss it to him. In addition, if an iPhone is functioning properly and you are not upgrading or switching phones, there is no need for you to remove the SIM card. Removing the card will expose it to the elements, adding to the risk of problems.