Install a scan tool.

Does the scan tool power up?

Go to Step 2

Go to Scan Tool Does Not Power Up

1. Disconnect the VIU from the E & C Serial Data circuit.
2. Turn ON the ignition, with the engine OFF.
3. Attempt to communicate with the radio.

Does the scan tool communicate with the radio?

Go to Step 8

Go to Step 3

Test the battery positive voltage circuit(s) and ignition voltage circuit(s) of the Radio for an open. Refer to Control Module References in Body Control System for appropriate schematic. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 4

1. Turn OFF the ignition.
2. Test the ground circuit(s) of the Radio for an open.

Did you find and correct the condition?

Go to Step 8

Go to Step 5

1. Disconnect the scan tool.
2. Test the E & C Serial Data circuit for a short or an open.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

Inspect for poor connections between the DLC connector terminal 14 and the E & C Serial Data terminal of 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 8

Go to Step 7

Replace the Radio. Refer to Control Module References in Body Control System for the appropriate repair procedure.

Did you complete the repair?

Go to Step 8

--

1. Reconnect the VIU.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Attempt to communicate with the VIU.

Does the scan tool communicate with the VIU?

Go to Step 14

Go to Step 9

Test the battery positive voltage circuit(s) and ignition voltage circuit(s) of the VIU for an open. Refer to Control Module References in Body Control System for appropriate schematic. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

1. Turn OFF the ignition.
2. Test the ground circuit(s) of the VIU for an open.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

1. Disconnect the scan tool.
2. Test the E & C Serial Data circuit for an open.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

Inspect for poor connections between the DLC connector terminal 14 and the E & C Serial Data terminal of the VIU. 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 14

Go to Step 13

Replace the VIU. Refer to Control Module References in Body Control System for the appropriate repair procedure.

Did you complete the repair?

Go to Step 14

--

Operate the Radio and VIU.

Do the Radio and VIU operate properly?

System OK

Go to Control Module References in Body Control System for the appropriate system check