With Powertrain Control Module (PCM)

DLC Connectors:

ACCESSING CODES
Although it is recommended that a diagnostic scan tool be used to read Diagnostic Trouble Code (DTC)(s), it may be possible to flash trouble codes on certain vehicles equipped with a "16" pin Data Link Connector (DLC) and a Powertrain Control Module (PCM). The DLC connector terminal "6" (diagnostic terminal, if equipped) is the third terminal from the left of the DLC connector's top row. The terminal is grounded by connecting it to terminal "5" (internal PCM ground), the terminal to the left of terminal "6" on the top row of the DLC connector.

Once terminals "5" and "6" have been connected, the ignition switch must be moved to the "ON" position, with the engine not running. At this point, the MIL (Service Engine Soon) should flash Diagnostic Trouble Code (DTC) 12 three times consecutively. This would be the following flash sequence: "flash, pause, flash-flash, long pause, flash, pause, flash-flash, long pause, flash, pause, flash-flash." DTC 12 indicates that the diagnostic system is operating. If DTC 12 is not indicated, a problem is present within the diagnostic system itself, and should be referred to Diagnostic Charts. Testing and Inspection

Following the output of DTC 12, the MIL (Service Engine Soon) will indicate a diagnostic trouble code three times if a diagnostic trouble code is present, or it will continue to output DTC 12. If more than one diagnostic trouble code has been stored in memory, the diagnostic trouble codes will be output from the lowest to the highest, with each diagnostic trouble code being displayed three times.