How to Check For Clean ESNs Before You Buy a Used Phone


While you can save hundreds of dollars by purchasing a used phone rather than a brand new one, what should be a simple transaction can actually turn out to be a risky proposition and a major headache if there is an Electronic Serial Number (ESN) problem.

What’s an ESN, you ask? It’s used to identify phones built on CDMA technology, and each phone has its own unique ESN. Such phones usually don’t have SIM cards that are commonly used in smartphones. Your service provider will use your phone’s ESN to monitor its use and data consumption as well as to identify and authenticate it prior to allowing it to connect to the network. So, you need to check for clean ESN if you want a phone that you can actually use.

Read on for a look at problems you can face if your ESN is bad, how you can check for clean ESN before you fork over your money to buy a used phone, and how you can avoid the problem altogether.

The Problem with Bad ESNs

If your ESN is deemed to be bad, what this means is that your phone won’t be able to connect to a CDMA network. So, you’ll be the owner of a phone that won’t be good for much more than listening to MP3s, storing contact information, or playing video games. There are numerous reasons why an ESN can be termed bad. For instance, if the phone has been flagged as lost or stolen, it will be flagged so that you can’t get carrier service.

Another reason why a phone may be deemed to have a bad ESN is if the person who previously owned the phone has an unpaid balance on his or her account. In such a scenario, the amount owing to the carrier will be passed onto you, and you won’t be able to register as the phone’s new owner until the outstanding balance is covered. You should also know that carriers do work together sometimes, and their collaborative database listing stolen phone IDs is one such example. That’s why you must exercise caution when buying a used phone.

How to Check for Clean ESN

If you do your homework before buying a used phone, you’ll be able to avoid any problems relating to bad ESN issues. Indeed, there’s absolutely no reason why you or anyone should find yourself in the situation of buying a used phone that, due to ESN problems, is virtually useless. Check out the following steps in order to find out how to check for clean ESN before buying.

  1. Online Check: There are numerous sites online where you can enter the ESN of the phone you’re interested in buying to see whether or not the ESN is valid. Before you can do this, however, you’ll need the seller to provide you with the ESN. Many sellers will, if advertising their used phones online, include all sorts of pictures, including one or more with the ESN displayed. If this is not the case in your situation, just ask for it. If the seller is reluctant or flat out refuses to honor your request for an ESN picture, by no means should you go through with a transaction.
  1. Check with Carrier Before Sealing the Deal: If you use an online classified ad site and plan to meet up with the seller to close the transaction, ensure that you call the carrier before exchanging the phone for your money. This will allow you to verify that the phone you can now see up close and personal has a good ESN.

How to Avoid the Problem Altogether

Another thing to consider is that you’re less likely to encounter such problems on sites like eBay and Amazon since they have policies in place to protect consumers and reviews of sellers to help you make a buying decision. Also, carriers sell used and refurbished phones that you can be sure have good ESNs. On the other hand, sites like Craigslist are like the Wild Wild West of the World Wide Web since you never really know who you’re negotiating with.

Buying a used phone can definitely make a world of sense when you consider how much money you can save in the process. If you proceed with caution and check for clean ESN before handing over your money, you’ll get the phone you want at a price you can definitely live with.

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