GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Seville 🢒 Body and Accessories 🢒 Data Link Communications 🢒 Diagnostic System Check - Data Link Communications

Step

Action

Value(s)

Yes

No

1
  1. Connect a scan tool.
  2. Turn the ignition switch to RUN.
  3. Attempt to establish communication with the vehicle.

Does the scan tool communicate?

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Go to Step 2

Go to Data Link Communications System Check

2

Display the DTCs with the scan tool.

Are there any loss of class 2 serial data communications DTCs set? (loss of class 2 serial data communications DTCs have the form of UXXXX)

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Go to Diagnostic Trouble Code (DTC) List

System OK