Scan Tool Does Not Power Up

CIRCUIT DESCRIPTION
The data link connector (DLC) provides operating power for the scan tool at terminal 16 for battery positive voltage, and at terminal 4 for ground. The scan tool will power up with the ignition off. The DLC provides the signal ground at terminal 5, class 2 serial data signal at terminal 2, UART serial data signal at terminal 9 and E and C serial data signal at terminal 14.

TEST DESCRIPTION

Steps 1-4:

The numbers below refer to the step numbers on the diagnostic table.
1. The CIG LTR fuse supplies power to terminal 16 of the DLC.
4. The battery positive voltage and ground circuits of the DLC are functioning properly. The malfunction must be due to the scan tool.