Scan Tool Does Not Communicate With A Class 1 Module

To perform diagnosis, see Fig 1 and Fig 2 .

Fig 1: Scan Tool Does Not Communicate With A Class 1 Module Diagnostic Flowchart (1 Of 2)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Scan Tool Does Not Communicate With A Class 1 Module Diagnostic Flowchart (2 Of 2)

Courtesy of GENERAL MOTORS CORP.