Diagnostic Aids

Some scan tools may require an external power supply. Ensure the scan tool is correctly connected to the power feed.

Ensure that the correct application (model year, carline, VIN code) has been selected on the scan tool. If communications are still not established, try the scan tool on another vehicle in order to ensure that the scan tool or the connecting cables are not the cause of the malfunction. Always try the scan tool on a vehicle that uses the same DLC terminal for serial data communication.

Any circuitry that is suspect to an intermittent complaint should be thoroughly inspected for the following:

• Backed-out terminals
• Improper mating of terminals
• Broken electrical connector locks
• Improperly formed or damaged terminals
• Faulty terminal-to-wiring connections
• Physical damage to the wiring harness
• A broken conductor inside the wire insulation
• Corrosion of the electrical connections, the splices, or the terminals