Without Scan Tool

Data Link Connector(DLC):

ACCESSING CODES
The means of communicating with the control module is the Data Link Connector (DLC) located under the instrument panel and is sometimes covered by a plastic cover labeled "DIAGNOSTIC CONNECTOR." The DLC is used in the assembly plant to receive engine information to determine proper operation before it leaves the plant. The DTC(s) stored in the control module memory can be displayed either through the Tech 1 scan tool, a hand-held diagnostic scanner plugged into the DLC connector, or by counting the number of flashes of the Malfunction Indicator Lamp (MIL) "Service Engine Soon" when the diagnostic terminal of the DLC is grounded. The DLC terminal "B" (diagnostic terminal) is the second terminal from the right of the DLC top row. The terminal is most easily grounded by connecting it to terminal "A" (internal control module ground), which is located to the right of terminal "B" on top row of the DLC.

When terminals "A" and "B" have been connected, the ignition switch turned to the "ON" position with the engine not operating, the MIL (Service Engine Soon) should flash Diagnostic Trouble Code (DTC) 12 three times consequently. This will 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 control module diagnostic system is operating properly. If the DTC 12 is not indicated, and a fault is present within the diagnostic system itself, it should be addressed by consulting the appropriate diagnostic chart. Refer to Diagnostic Trouble Code Charts.

INTERMITTENT MALFUNCTION INDICATOR LAMP
The malfunction indicator lamp will indicate a Diagnostic Trouble Code (DTC) three tinies if a DTC is present, or it will simply continue to output DTC 12. If more than one diagnostic trouble code has been stored in the control module memory, the DTC(s) will be displayed from the lowest to the highest with each DTC being displayed three times.

A corresponding DTC will be stored in the memory of the PCM as a history DTC until DTCs have been cleared. When unexpected DTCs appear during the code reading process, one can assume that these DTCs were set by an intermittent malfunction and could he helpful in diagnosing the system.

An intermittent DTC may or may not re-set. If it is an intermittent failure. a Diagnostic Trouble Code (DTC) chart is not used. Consult the "Diagnostic Aids" on the diagnostic chart corresponding to the intermittent DTC. Refer to Intermittents. A physical inspection of the applicable sub-system most often will not resolve the problem.