For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: In order to avoid a misdiagnosis, inspect for stored diagnostic trouble codes (DTCs). Refer to the On-Board Diagnostic System Check in Engine Controls.
1 | Did you perform the System Check? | -- | Go to Step 2 | Go to Radio/Audio System Check
2 | Attempt to duplicate the complaint condition in each ignition switch key position. Is the complaint condition verified? | -- | Go to Step 3 | Go to Step 4
3 |

1. Acquire any available technical service bulletins.
2. Perform the Antenna System Test. Refer to Antenna Diagnostic Check .
3. Attempt to duplicate the complaint condition again.

Is the repair complete?

--

Go to Radio/Audio System Check

Go to Step 5

4 | Contact the customer for an explanation of the complaint condition. Has the customer clerified the complaint condition? | -- | Go to Radio/Audio System Check | --
5 | Is the complaint condition only present with the ignition key in the RUN position and the engine running? | -- | Go to Step 7 | Go to Step 6
6 | Is the vehicle equipped with aftermarket electronic equipment? | -- | Go to Step 8 | Go to Step 9
7 | Is the vehicle equipped with aftermarket electronic equipment? | -- | Go to Step 16 | Go to Step 17
8 | Verify the proper installation of the aftermarket electronic equipment. Did installation follow the GM guidelines? | -- | Go to Step 9 | Go to Step 10
9 | Remove the fuses and the circuit breakers, one at a time, until the complaint condition is eliminated. Is the complaint condition eliminated? | -- | Go to Step 11 | Go to Step 12
10 | Correct the installation. Is the repair complete? | -- | Go to Radio/Audio System Check | --
11 |

1. Mark the complaint fuses.
2. Reinstall all of the fuses and the circuit breakers. Refer to Power Distribution in Electrical Diagnosis in order to identify all the systems and the components powered by the complaint fuses or circuit breakers.
3. Disconnect the components which are powered by the compoaint fuses, one at a time, until the complaint condition has been eliminated.

Have you identified the complaint-causing component?

--

Go to Step 13

Go to Step 15

12 | Refer to the Sound Service Audio Systems Diagnostic Guide for further instructions. Have you referred to the Sound Service Guide? | -- | Go to Radio/Audio System Check | --
13 | Inspect the ground integrity of the complaint-causing component. Is the component OK? | -- | Go to Step 15 | Go to Step 14
14 | Make the necessary repair. Is the repair complete? | -- | Go to Radio/Audio System Check | --
15 | Refer to the Sound Service Audio Systems Diagnostic Guide for further instructions. Have you referred to the Sound Service Guide? | -- | Go to Radio/Audio System Check | --
16 | Verify proper installation of the aftermarket electronic equipment. Were the GM aftermarket installation guidelines followed? | -- | Go to Step 17 | Go to Step 20
17 |

1. Inspect the system for stored Diagnostic Trouble Codes (DTCs). Refer to Drivability and Emissions in Engine Controls.
2. Test the ignition system, including the following conditions. Refer to Ignition System.

• | Proper spark wire routing

• | No misfiring

3. Test all of the engine compartment grounds.
4. Inspect the following components for malfunctions that may cause poor reception:

• | Relays

• | Solenoids

• | Other components

Are all of the components in working order?

--

Go to Step 19

Go to Step 18

18 | Make the necessary repairs. Is the repair complete? | -- | Go to Radio/Audio System Check | --
19 | Refer to the Sound Service Audio Systems Diagnostic Guide for further instructions. Have you referred to the Sound Service Guide? | -- | Go to Radio/Audio System Check | --
20 | Correct the installation. Is the repair complete? | -- | Go to Radio/Audio System Check | --