Checking The Wiring

The signal for the lighting for the Volvo On Call buttons is pulse width modulated. To enable measuring and checking if there is a problem on the lead, pulse-width modulation (lighting intensity) needs to be set to a specific value.

To check whether the fault is due to an open circuit, or short-circuit to ground, the value 10% must be set.
To check if the signal has a short-circuit to voltage, the value 0% must be set.

Click on VCT2000 to set the desired value on the signal.

Open-circuit or short-circuit to ground

Read the voltage between terminal #A:3 and #A:6 to check the SOS button.
Read the voltage between terminal #A:4 and #A:6 to check the On Call button.
If the value is lower than 3 V, the cable has a short-circuit to ground.
If the measured value is greater than 8 V, this means that the cable is disconnected and that the circuit is open.
Check the wiring and connectors

short-circuit to voltage

Read the voltage between terminal #A:3 and #A:6 to check the SOS button.
Read the voltage between terminal #A:4 and #A:6 to check the On Call button.
If the value is greater than 8 V, the cable has a short-circuit to voltage.
Check the wiring and connectors

Remedy as necessary.

Other information

Fig 1: Identifying VCT2000 Diagnostic Tool Symbol In VIDA (Volvo scan tool)

Courtesy of VOLVO CARS CORPORATION

Fig 2: Identifying SOS and ON CALL Switches

Courtesy of VOLVO CARS CORPORATION

Was a fault detected?

YES
Refer to VERIFICATION
NO
Refer to CHECKING THE COMPONENT