How to Read OBD2 Codesby Contributor
Since 1996, every car manufactured has been required to have an Onboard Diagnostic system by law. This system monitors a car's performance and will alert the driver when it detects any problems. The codes can be downloaded and read with an OBD2 code reader or recorded with the help of the "Check Engine" light on the dashboard and a jumper wire.
Use an OBD2 Code Reader
Purchase an OBD2 reader from a website like OBD Codes (see Resources below). OBD2 readers are available as personal handheld readers or professional readers for auto technicians. Personal readers are less complicated but will do the job of retrieving and translating the OBD2 codes.
Connect the OBD2 reader to your car. Locate the 16-pin female connector inside your car, which is most likely in the foot well of the driver's side. Link the code reader to the connector with the adapter cable.
Wait for the reader to initialize. The code reader will check your car's computer to find out what protocol to use and then connect. Once the reader has connected, it will read the codes given by the computer and display it.
Check your service manual for an interpretation of the code. Although some personal OBD2 code readers, like Innova's Digital Canobd2 Tool and the Canscan K900 Code Reader, are equipped to display the definitions of the codes, others are not. Low-end personal code readers will only display the code generated by your car's computer.
Read the Diagnostic Trouble Codes Without an OBD2 Code Reader
Locate the 16-pin data link connector. Connect the jump wire to terminals 4 and 9 of the connector. Turn the key to the "On" position without starting the engine.
Watch the "Check Engine" light. This light will begin to flash in specific patterns to indicate a 1- or 2-digit Diagnostic Trouble Code. The flashes will be long for the first digit, short for the second digit and blank if the digit is 0.
Record all the codes given. The "Check Engine" light will display the codes in sequence and then keep repeating them in order. Refer to your repair manual to check for the meaning of the codes.
- Make sure your engine is off before connecting to the 16-pin port.
- There is a risk of electrical damage to your car's computer if you do not connect the jumper wire to the correct terminals.