GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

1

Did you review the Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Radio/Audio System Description and Operation

2

Turn the ignition ON and the radio ON.

Does the system operate normally?

--

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

Go to Step 3

3

Inspect the radio connector for poor or loose connection. 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 20

Go to Step 4

4

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

Did you find and correct the condition?

12 V

Go to Step 20

Go to Step 5

5

Test for an open or high resistance in the accessory voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

12 V

Go to Step 20

Go to Step 6

6

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

Did you find and correct the condition?

Ground Potential

Go to Step 20

Go to Step 7

7

Is the vehicle equipped with RPO UE1 OnStar®?

--

Go to Step 8

Go to Step 11

8

Disconnect the 12-way radio connector.

Does the system operate normally?

--

Go to Step 9

Go to Step 11

9

Check for a short to ground on the OnStar mute circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 10

10

Replace the OnStar® vehicle communication interface module (VCIM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is the repair complete?

--

Go to Step 20

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11

Is the vehicle equipped with an amplifier (RPO U67)?

--

Go to Step 12

Go to Step 17

12

Measure the voltage at the amplifier 24-way connector radio on the amplifier control circuit.

Is the measured voltage equal to the specified value?

12 V with key ON

Go to Step 14

Go to Step 13

13

Test for an open or high resistance in the radio on the amplifier control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 14

14

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

Did you find and correct the condition?

12 V at all times

Go to Step 20

Go to Step 15

15

Test for an open or high resistance in the ground circuit to the amplifier. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Ground potential

Go to Step 20

Go to Step 16

16

  1. The amplifier is disconnected.
  2. The radio is ON at maximum volume.
  3. Using the DVOM, measure the AC voltage between the LF (+) and the LF (-) circuits at the amplifier connector.

Is the voltage equal to or greater than the specified value?

0.50 V AC

Go to Step 18

Go to Step 17

17

Disconnect the radio 24-way connector and test for a short to power or a short to ground on all the speaker output circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

18

Replace the amplifier. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is the repair complete?

--

Go to Step 20

--

19

Replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is the repair complete?

--

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2