Without Scan Tool

12 Pin Data Link Connector (DLC):

DATA LINK CONNECTOR (DLC)
The provision for communicating from vehicle to scanner is the DLC. It is usually located under the instrument panel and is sometimes covered by a plastic cover labeled "DIAGNOSTIC CONNECTOR." It is used in the assembly plant to receive information in checking that the engine is operating properly before it leaves the plant. The connector can also be used by the service technician to identify Powertrain Control Module (PCM) stored trouble codes.

FLASHING DIAGNOSTIC TROUBLE CODES (DTC) WITH THE 12 PIN DLC CONNECTOR (PIN "B" INCLUDED)
A diagnostic scan tool must be used to read diagnostic trouble codes unless the vehicle has a 12 pin DLC connector equipped with a DLC connector terminal "B". The DLC connector terminal "B" (if equipped) is the second terminal from the right of the DLC connector's top row. The terminal is grounded by connecting terminal "B" to terminal "A" (internal PCM ground). Both terminals are located to the right side, and on the top row of the DLC connector.

Once terminals "A" and "B" have been connected, the ignition switch must be moved to the "ON" position, with the engine not running. At this point, the MIL should flash 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." Diagnostic Trouble Code (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 the appropriate diagnostic chart.

Following the output of DTC 12, the Malfunction Indicator Lamp (MIL) will indicate a DTC three times if a DTC is present, or it will continue to output DTC 12. If more than one DTC has been stored in memory, the DTCs will be output from the lowest to the highest, with each DTC being displayed three times.