With Manufacturer's Scan Tool

DLC Connectors:

ACCESSING CODES
The recommended method for reading Diagnostic Trouble Code (DTC)s stored in memory is by using a diagnostic scan tool plugged into the Data Link Connector (DLC). Follow instructions supplied by tool manufacturer.

SCAN TOOL USE WITH INTERMITTENTS
In some scan tool applications, the data update rate makes the scan tool less effective than a voltmeter when trying to detect an intermittent problem which lasts for a very short time. However, the Tech 1 scan tool allows manipulation of wiring harnesses or components under the hood with the engine not operating, while observing the readouts.

The Tech 1 scan tool can be plugged in with data displayed while driving the vehicle when the malfunction indicator lamp turns "ON" momentarily or when engine driveability is momentarily poor. If the problem is related to certain parameters that can be checked by the Tech 1, this should be done while driving the vehicle. If there does not seem to be any correlation between the problem and any specific circuit, the Tech 1 scan tool can display each parameter, for any period of time to observe any change in the readings which might indicate an intermittent operation.

Compare Readings to Known Good Component
The Tech 1 scan tool is used to compare the operating parameters of a poorly operating engine with those of a known good one. For example, a sensor may shift in value but not set a diagnostic trouble code. Comparing the sensor's readings with those of a known good vehicle may locate the fault

Operation and Limitations
The Tech 1 scan tool has the ability to save time in diagnosis and prevent the replacement of good parts. The key to using the Tech 1 scan tool successfully for diagnosis is in the technician's ability to understand the system he is trying to diagnose, as well as, an understanding of the Tech 1 scan tool's operation and limitations. The technician should use the tool manufacturer's operating manual to become familiar with the tool's operation.