GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

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 known strong AM station then to a known strong FM station.

Is the radio reception clear?

--

Go to Audio System Troubleshooting Hints

Go to Step 3

3

  1. Disconnect the negative battery cable.
  2. Remove the radio. Refer to Radio Replacement for service procedure.
  3. Important: Always zero out the digital multimeter (DMM) before taking a resistance measurement to ensure an accurate reading.

  4. Measure the resistance between the negative battery cable and the radio antenna coaxial ground at the radio.

Does the resistance measure greater than the specified value?

0.20 ohms

Go to Step 4

Go to Step 5

4

Test the antenna module ground for an open or high resistance. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 6

5

    Important: Always zero out the digital multimeter (DMM) before taking a resistance measurement to ensure an accurate reading.

  1. Remove the antenna coaxial cable from the radio and antenna module.
  2. Measure the resistance of the antenna cable center conductor between the radio and the antenna module.

Does the resistance measure greater than the specified values?

RG-58/RG-59 Coax: 0.20 ohms

RG-62/RG-62M Coax: 3.5 ohms

Go to Step 7

Go to Step 8

6

Replace the antenna coaxial cable.

Did you complete the replacement?

--

Go to Step 15

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7

  1. Test the antenna cable center conductor for an open or high resistance. Refer to Circuit Testing and in Wiring Systems.
  2. Inspect the antenna coaxial cable for a poor connection and corrosion. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 6

8

  1. Test for continuity between the antenna coaxial cable center conductor and metal case
  2. Test at the opposite end of the cable also.

Did you measure continuity?

--

Go to Step 6

Go to Step 9

9

  1. Reconnect the antenna coaxial cable to the radio.
  2. Reconnect the negative battery cable.
  3. Disconnect connector C1 from the antenna module.
  4. Turn ON the ignition, with the engine OFF.
  5. Turn ON the radio.
  6. Measure the voltage at connector C1 terminal A.

Did you measure battery voltage?

--

Go to Step 10

Go to Step 11

10

Inspect for poor connections at the antenna module. 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 15

Go to Step 12

11

Test CKT 145 for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

12

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

Did you complete the replacement?

--

Go to Step 15

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13

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 15

Go to Step 14

14

Replace the radio and perform the set up procedure. Refer to Radio Replacement and Radio Setup .

Did you complete the replacement?

--

Go to Step 15

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15

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2