Schematic Reference: Radio/Audio System Schematics

Did you review the Radio/Audio System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Radio/Audio System Description and Operation

1. Turn ON the ignition, with the engine OFF.
2. Turn ON the radio.

Does the radio display LOC?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Is the security code known?

Go to Step 6

Go to Step 4

1. Turn ON the ignition, with the engine OFF.
2. Press and hold the radio preset buttons 2 and 3 for approximately 8 seconds until the first 3 digits of the backup code are displayed on the radio.
3. Record the displayed code.
4. Press and hold the AM/FM push button until the second 3 digits are displayed on the radio.
5. Record the displayed code.

Could you successfully extract the code?

Go to Step 5

Go to Step 7

Contact Delco Electronics in order to give them the backup code information and to obtain an unlock code.

Did you complete the action?

Go to Step 6

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Important:: If 8 unsuccessful tries are made to unlock the radio, the display will return to the LOC display, but when the SET button is pressed, INOP will be displayed. This means that the radio must be left powered up for 1 hour with the battery and the ignition applied before any more attempts to unlock the radio can be made. Anytime INOP is displayed, 3 more attempts will be allowed after the 1 hour waiting period with the battery and ignition applied.

1. Ensure that the code to be used is correct.
2. Turn ON the ignition, with the engine OFF.
3. Press the MN button for Avalanche, Tahoe, Yukon, Suburban, Denali /Seek right button for Escalade until 000 is displayed.
4. Press and hold the HR button for Avalanche, Tahoe, Yukon, Suburban, Denali / Seek left button for Escalade until the last 2 digits agree with the code.
5. Press and hold the MN button forTahoe, Denali / Seek right for Escalade until the first 2 digits agree with the code.
6. Press the AM/FM button when the complete code is displayed. If REP appears on the display, repeat this step.

Did you successfully complete the action?

Go to Step 8

Go to Step 7

Replace the radio. Refer to Radio Replacement.

Did you complete the replacement?

Go to Step 8

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Operate the system in order to verify the repair.

Did you complete the repair?

System OK

Go to Step 2