With Manufacturer's Scan Tool

ALDL Connector:

Tool manufacturers have developed "Scan" tools to interface with the diesel electronic control system, through the ALDL. It supplies a visual reading of most inputs to the control module and some outputs. Review the tool instruction manual to understand its operation and limitations.

OPERATION
Follow SCAN manufactures instructions for extracting trouble codes.

NOTE:
Not all SCAN testers are compatible with every system. A SCAN tool that produces faulty readings should NOT be used, and the problem should be reported to the tool manufacturer. Use of a faulty SCAN tool can result in improper diagnosis and unnecessary component replacement.