Loss Of Communication On Private Bus - SDARS

LOSS OF COMMUNICATION ON PRIVATE BUS - SDARS

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition in run, and the IOD fuse installed.

- Set Condition:
The radio does not receive any messages from the Satellite Receiver for at least 12 seconds.





Diagnostic Test

1. AUDIO BUS 2 SHORT TO GROUND
Turn the ignition off.
Disconnect the Satellite Receiver Module harness connectors.
Disconnect the Satellite Radio Multiplexer harness connectors.
Measure the resistance between ground and the Audio Bus 2 circuit.
Is the resistance below 100 ohms?

Yes

- Repair the Audio Bus 2 circuit for a short to ground between the Satellite Receiver Module and the Multiplexer.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To2

2. AUDIO BUS 2 OPEN
Turn the ignition off.
Disconnect the Satellite Receiver Module harness connectors.
Disconnect the Satellite Radio Multiplexer harness connectors.
Measure the resistance of the Audio Bus 2 circuit between the Satellite Receiver Module and the Multiplexer.
Is the resistance below 5.0 ohms?

Yes

- Go To3

No

- Repair the Audio Bus 2 circuit for an open between the Satellite Receiver Module and the Multiplexer.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

3. AUDIO BUS 2 SHORT TO VOLTAGE
Turn the ignition off.
Disconnect the Satellite Receiver Module harness connectors.
Disconnect the Satellite Radio Multiplexer harness connectors.
Turn the ignition on.
Measure the voltage of the Audio Bus 2 circuit.
Is the voltage above 2 volts?

Yes

- Repair the Audio Bus 2 circuit for a short to voltage between the Satellite Receiver Module and the Multiplexer.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To4

4. AUDIO BUS 1 SHORT TO GROUND
Turn the ignition off.
Disconnect the Satellite Radio Multiplexer harness connectors.
Disconnect the Radio harness connector.
Measure the resistance between ground and the Audio Bus 1 circuit.
Is the resistance below 100 ohms?

Yes

- Repair the Audio Bus 1 circuit for a short to ground between the Radio and the Multiplexer.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To5

5. AUDIO BUS 1 OPEN
Turn the ignition off.
Disconnect the Radio harness connector.
Disconnect the Satellite Radio Multiplexer harness connectors.
Measure the resistance of the Audio Bus 1 circuit between the Radio and the Multiplexer.
Is the resistance below 5.0 ohms?

Yes

- Go To6

No

- Repair the Audio Bus 1 circuit for an open between the Radio and the Multiplexer.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

6. AUDIO BUS 1 SHORT TO VOLTAGE
Turn the ignition off.
Disconnect the Radio harness connector.
Disconnect the Satellite Radio Multiplexer harness connectors.
Turn the ignition on.
Measure the voltage of the Audio Bus 1 circuit.
Is the voltage above 2 volts?

Yes

- Repair the Audio Bus 1 circuit for a short to voltage between the Radio and the Multiplexer.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To7

7. MULTIPLEXER INTERNAL FAILURE
Turn the ignition off.

NOTE: Disconnect the Satellite Receiver Module harness connectors and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.

NOTE: Disconnect the Satellite Radio Multiplexer harness connectors and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.

NOTE: Disconnect the Radio harness connector and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors, repair as necessary. Pay particular attention to all Power and Ground circuits.
Replace the Satellite Radio Multiplexer.
Reconnect harness connectors and start the engine.
Attempt to reset the DTC.
Does the DTC reset?

Yes

- Go To8

No

- Test Complete.

8. SATELLITE RECEIVER MODULE
Replace the Satellite Receiver Module.
Start the vehicle and operate the Satellite Radio.
Attempt to reset the DTC.
Does the DTC reset?

Yes

- Go To9

No

- Test Complete.

9. RADIO INTERNAL FAILURE
If there are no other possible causes remaining, view repair.

Repair

- Replace the Radio.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.