GM Service Manual Online
For 1990-2009 cars only

Radio Poor Reception Coupe

Step

Action

Value(s)

Yes

No

DEFINITION: This table is used for diagnosing an audio system that has poor sound quality with the radio on. Normal sound is heard whenever the tape player or CD player is used.

1

Were you sent here from the Radio Audio Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Radio/Audio System

2

Verify the condition with the stations that are normally received in your area.

Is the sound quality less than normal system operation?

--

Go to Step 3

System OK

3

Compare the sound quality with the engine running, to the sound quality with the ignition ON engine OFF.

Is the sound quality within normal system operation with the engine OFF?

--

Go to Speaker Noise - Accessory

Go to Step 4

4

  1. Disconnect the antenna cable from the radio.
  2. Temporarily mount a test antenna to the vehicle.
  3. Ground the antenna base and test the ground with a DMM before connecting the antenna cable to the radio.
  4. Test the radio sound quality with the stations that are normally received in your area.

Is the sound quality within normal system operation?

--

Go to Step 5

Go to Step 13

5

Inspect the condition of the antenna grids and jumper wires. Repair and replace as necessary.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 6

6

  1. Disconnect the radio connector C1 and the antenna module connector.
  2. Test circuit 145 for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 7

7

Test circuit 314 between the radio connector C1 and radio antenna module connector, for an open or high resistance and a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 8

8

Test the radio antenna cable's center conductor wires and braided wire shields for the following conditions:

    • Open or high resistance.
    • Short to ground (center conductor).
    • Continuity between the center conductor and braided wire shield.

Refer to Circuit Testing in Wiring Systems.

Did you find any of the conditions listed present in any of the antenna cables?

--

Go to Step 9

Go to Step 10

9

Replace the defective antenna cable. Refer to the following procedures:

Did you complete the repair?

--

Go to Step 14

--

10

Test the antenna buffer for any of the following conditions:

    • Poor case ground.
    • Open or high resistance in the center conductor circuit or the shield circuit.
    • Short to ground (center conductor circuit).
    • Continuity between the center conductor circuit and the shield circuit.

Did you find any of the conditions listed present in the antenna buffer?

--

Go to Step 11

Go to Step 12

11

Replace the antenna buffer. Refer to Antenna Buffer Replacement .

Did you complete the repair?

--

Go to Step 14

--

12

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

Did you complete the repair?

--

Go to Step 14

--

13

Replace the radio. Refer to Radio Replacement .

Did you complete the repair?

--

Go to Step 14

--

14

  1. Clear any DTCs which may have set.
  2. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Diagnostic System Check - Radio/Audio System

Radio Poor Reception Convertible and Hardtop

Poor Reception (Convertible and Hardtop)

Step

Action

Value(s)

Yes

No

DEFINITION: This table is used for diagnosing an audio system that has poor sound quality with the radio ON and a normal operating power antenna (convertible). Normal sound is heard whenever the tape player or the CD player is used.

1

Were you sent here from the Radio Audio Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Radio/Audio System

2

Verify the condition with the stations that are normally received in your area.

Is the sound quality less than normal system operation?

--

System OK

Go to Step 3

3

Compare the radio sound quality with the engine running, to the sound quality with the ignition ON engine OFF.

Is the sound quality within normal system operation with the engine OFF?

--

Go to Speaker Noise - Accessory

Go to Step 4

4

  1. Disconnect the antenna cable from the radio.
  2. Temporarily mount a test antenna to the vehicle.
  3. Ground the antenna base and check the ground with a DMM before connecting the antenna cable to the radio.
  4. Test the radio sound quality with the stations that are normally received in your area.

Is the sound quality within normal system operation?

--

Go to Step 5

Go to Step 10

5

  1. Carefully inspect the radio power antenna assembly.
  2. Inspect both grounds straps for looseness or corrosion.
  3. Inspect all mounting points for the radio power antenna assembly.
  4. Inspect all related wiring and connectors at the radio power antenna.

Are the ground straps, mounting hardware, and related wiring in good condition?

--

Go to Step 7

Go to Step 6

6

Repair the ground straps, mounting hardware, or related wiring concern. Refer to Antenna Cable Strap Replacement .

Did you complete the repair?

--

Go to Step 11

--

7

Test the radio antenna cable center conductor wire and braided wire shield for the following conditions:

    • Open or high resistance.
    • Short to ground (center conductor).
    • Continuity between the center conductor and braided wire shield.

Refer to Circuit Testing in Wiring Systems.

Did you find any of the conditions listed present in the antenna cable?

--

Go to Step 8

Go to Step 9

8

Replace the coaxial cable between the radio and radio power antenna. Refer to Radio Antenna Cable Extension Cable Replacement .

Is the repair complete?

--

Go to Step 11

--

9

Replace the radio antenna assembly. Refer to Power Antenna Assembly Replacement or Radio Antenna Replacement .

Is the repair complete?

--

Go to Step 11

--

10

Replace the radio. Refer to Radio Replacement .

Is the repair complete?

--

Go to Step 11

--

11

  1. Clear any DTCs which may have set.
  2. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Diagnostic System Check - Radio/Audio System