How to Find Diagnostic Trouble Codes for a 1990 Cadillac

Once you retrieve the On-Board Diagnostic trouble codes from your 1990 Cadillac, you will have to find a definition for each On-Board Diagnostic code that appeared on the scanner. Quite often, the scanner's owner manual will contain a list of generic codes. If the manual doesn't, those codes are easily found online.

• 1

  Hook the scanner up to the Cadillac's computer outlet. This diagnostic port will be located under the dashboard and the steering wheel. You will not need tools to uncover it.

• 2

  Turn the scanner on.

• 3

  Turn the Cadillac on. The diagnostic system will automatically connect with the scanner, and the "trouble codes" will appear on screen. You don't have to press any buttons or enter any commands to retrieve them. Take a pen and paper and write these codes down.

• 4

  Turn both the Cadillac and the scanner off. Remove the scanner's plug from the outlet.

• 5

  Consult your scanner owner's manual or go online and access an OBD codes website, such as the one given in the Resources section.

• 6

  Scroll down the list of alpha-numeric trouble codes and find the ones that came up on the scanner.

• 7

  Read the code's definition. These definitions will be descriptions of problems that activated the "Check Engine" light on the Cadillac.