Scan Tool Inoperative

The data link connector (DLC) provides operating power for the scan tool at terminal 16 (battery positive voltage) and at terminal 4 (ground). The DLC provides the class 2 serial data signal at terminal 2 and signal ground at terminal 5. The scan tool will power up with the ignition off. Many modules, however, will not communicate unless the body control module (BCM) detects that the ignition is on and sends the appropriate power mode message.

1. Test the battery positive voltage circuit of the DLC for an open or a short to ground. If there is no fault, go to next step.
2. Test the ground circuit at terminal 4 of the DLC for an open or a short to ground. If there is no fault, go to next step.
3. Inspect for poor connections at terminals 4 and 16 of the DLC. If there is no fault, go to next step.
4. The scan tool may be malfunctioning. Refer to the scan tool user guide.