Without Scan Tool

DLC:

ACCESSING CODES
The DTC(s) stored in the control module memory can be displayed either through the Tech 1 Diagnostic Computer, a hand-held diagnostic scanner plugged into the Data Link Connector (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 the top row of the DLC.

When terminals "A" and "B" have been connected, the ignition switch must be turned to the "ON" position with the engine not operating. The MIL (Service Engine Soon) 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." DTC 12 indicates that the control module diagnostic system is operating properly. If DTC 12 is not indicated, a fault is present within the diagnostic system itself, and should be addressed by consulting the appropriate diagnostic chart. Related Tests, Information and Procedures

Following the output of DTC 12, the malfunction indicator lamp will indicate a Diagnostic Trouble Code three times 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.

INTERMITTENT MALFUNCTION INDICATOR LAMP
In the case of an "Intermittent" problem, the MIL will light for ten (10) seconds and then will go out. However, the corresponding Diagnostic Trouble Code (DTC) will be stored in the memory of the control module unless the battery voltage to the control module has been removed. When unexpected DTC(s) appear during the code displaying process, assume that these DTC(s) were set by an intermittent malfunction and can be helpful in diagnosing the system.

An intermittent DTC may or may not reset. If it is an intermittent failure. a Diagnostic Trouble Code Chart WILL NOT be used. Consult the "Diagnostic Aids" for the the diagnostic trouble code chart corresponding to the intermittent code. Diagnosis by Symptom also covers the topic of "Intermittents." - Intermittent Malfunctions
A physical inspection of the applicable sub-system most often will resolve the fault.