Reading Diagnostic Trouble Codes

CHECK ENGINE LIGHT Pattern:

Turn ignition switch ON, OFF, ON, OFF, ON in less than 5 seconds, observe the CHECK ENGINE light. CHECK ENGINE light should flash a series of codes. Flashes will be separated by short or long pauses. A long pause indicates a change from "tens" to "ones" position, or a change to next code.
For example a single flash followed by a long pause and then 2 more flashes separated by a short pause and followed by a long pause would indicate a code 12.

FLASH........FLASH...FLASH........

A code 55 will be displayed at the end of the test.


NOTE: Information provided for those with no scan tool. In order to properly diagnose and repair vehicle, a scan tool should be used. For fault code diagnostic charts refer to TROUBLE CODE TO FAULT MESSAGE CONVERSION.