Install the scan tool.

Does the scan tool power up?

Go to Step 2

Go to Scan Tool Inoperative in Data Link Communications

1. Turn On the ignition, with the engine OFF.
2. Attempt to establish communication with the radio.

Does the scan tool communicate with the radio?

Go to Step 3

Go to Step 4

Select DTC Information for the radio.

Does the scan tool display any current B-Type DTCs?

Go to DTC List

Go to Step 5

Attempt to establish communications with the other modules connected to the Class 2 data link. (If using a Tech 2, the Class 2 Message Monitor feature can be used to obtain this information.)

Are there any modules on the Class 2 data link which are communicating?

Go to Step 6

Go to Scan Tool Does Not Communicate with Class 2 Data Line in Data Link Communications

Does the scan tool display any current U-Type DTCs?

Go to Diagnostic Trouble Code (DTC) List in Data Link Communications

Go to Step 7

1. Remove and inspect the RADIO BATT GUARD fuse for an open.
2. Inspect and test the battery feed circuit at terminal F1 for proper voltage (11-13 V).
3. Make necessary repairs.

Did you find and correct any conditions?

Go to Step 2

Go to Step 8

Does the scan tool display any history B-Type or U-Type DTCs?

Go to Step 9

Go to Radio/Audio System Check

Replace the radio.

Is the replacement complete?

Go to Radio/Audio System Check

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1. Review the appropriate DTC diagnostic table for the history DTC.
2. Review the diagnostic aids and the conditions for setting the DTC.

Did any DTC set as a current DTC, while attempting to locate the cause of the history DTC?

Go to the appropriate DTC List

Go to Radio/Audio System Check