S80 L5-2.5L Turbo VIN 59 B5254T2 (2004)
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Ignition on.
Activate buttons and read status on audio/telephone switch unit buttons.
If read-out gave a correct result the fault is not in the SWM unit.
Did read-out of status on audio/telephone switch unit give a correct result?
Yes - No Fault Found
No - Vehicle equipment
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Vehicle equipment
Is the vehicle equipped with RTI?
Yes - Checking the wires and components
No - Checking the wires and components