GM Service Manual Online
For 1990-2009 cars only

Radio Poor Reception w/o RPO UJ6

Step

Action

Value(s)

Yes

No

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

1

Did you perform the Radio/Audio System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Radio/Audio System

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the radio.
  3. Tune the radio to a several local AM stations then to a several local FM stations.

Is the radio reception clear?

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Go to Audio System Troubleshooting Hints

Go to Step 3

3

Inspect for proper connections at the antennas and the radio antenna module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 12

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the radio antenna module harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Turn ON the radio.
  5. Connect a test lamp between the battery positive voltage circuit and ground.

Does the test lamp illuminate?

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Go to Step 5

Go to Step 7

5

  1. Tune the radio to the FM band.
  2. Measure the voltage from the FM composite signal circuit of the radio antenna module to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 6

Go to Step 8

6

Test the antenna cables for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 12

Go to Step 10

7

Test the battery positive voltage circuit for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Test the FM composite signal circuit for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

9

Inspect for poor connections at the radio. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Important: Always perform the transmitter programming procedure for the radio antenna module. Refer to Transmitter Programming in Keyless Entry.

Replace the radio antenna module. Refer to Radio Antenna Module Replacement .

Did you complete the replacement?

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Go to Step 12

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11

Replace the radio. Refer to Radio Replacement .

Did you complete the replacement?

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Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2