An On-Board Diagnostic scanner can help check a Hyundai Elantra's engine. The service engine soon light does not need to be lit. The diagnostic system routinely monitors the engine for problems, and when a malfunction is sensed, the service light becomes active and a trouble code is issued. The Elantra's computer system, however, does not class every problem as trouble code worthy. The problem has to repeat itself a number of times. In the meantime, the system classes these faults as "pending." Retrieving pending codes is just as easy as pulling trouble codes.
Consult your scanner's user manual for trouble code definitions. Mark the page the list begins, and set it on top of your Elantra's dashboard.
Insert the Elantra's key into the ignition, but leave the engine and the electrical system off.
Locate the Elantra's data link connector below the dashboard. It will be uncovered and to the left of the steering column. Plug your OBD-II scanner into this outlet. What to do next will depend on the exact OBD-II scanner you have purchased. The process is fundamentally similar across brands, but there are variations and differing button configurations. CarMD's scanner, for example, does not require you to start your engine, but others like Actron's CP9125 does.
Start the Elantra's engine if your scanner calls for it. Also, some scanners will activate themselves once a connection is sensed with a diagnostic scanner. Some scanners have to be manually switched on.
Look at the trouble codes displayed on your screen. Scroll through these and look for codes that are "pending."
Consult the manual you left on the dashboard for code descriptions. OBD-II codes are divided into two general classes. There are generic codes universal to all vehicles OBD-II compliant vehicles. There are also codes that are particular to Hyundai vehicles. If you manual does not contain these codes, you will have to go online and find the codes at a non-Hyundai related website. If your scanner's manual does not contain the codes at all, it may be because it comes with a software package that needs to be installed on your home computer. These type of programs are meant to assist in vehicle diagnostics.
Turn the car off and disconnect the scanner from the data link connection. Use the code definitions to troubleshoot the engine. If the problems sound more advanced then your experience or skill level, consider driving the Elantra to a Hyundai approved mechanic.
