Check the control module
WARNING:
No ABS, stability and traction control functions are available when there is communication with the Brake control module (BCM) (Volvo Diagnostics are activated). ABS warning lamp flashes for as long as the diagnostics are activated. To cancel the diagnostics before test driving the vehicle, the ignition must be switched off
Model years -2001.
See Check the control module .
Model years 2002-.