Scan Tool Does Not Communicate With Class 2 Device

Scan Tool Does Not Communicate with Class 2 Device

Circuit Description
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. Connecting a scan tool to the data link connector (DLC) allows communication with the modules for diagnostic purposes.

Scan Tool Does Not Communicate With Class 2 Device (1 Of 2):

Scan Tool Does Not Communicate With Class 2 Device (2 Of 2):

Diagnostic Aids
The engine will not start when there is a total loss of class 2 serial data communication while the ignition is OFF. The following conditions will cause a total loss of class 2 serial data communication:
- A class 2 serial data circuit shorted to ground.
- A class 2 serial data circuit shorted to voltage.
- An internal condition within a module or connector on the class 2 serial data circuit, that causes a short to voltage or ground to the class 2 serial data circuit.