Checking the 15-supply to the control module

Fig 1: Identifying Ignition On Position

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Disconnecting Control Unit

Courtesy of VOLVO CARS OF NORTH AMERICA.

• The breakout box connected
• Control module disconnected.
• Ignition on.

  Check the 15-supply by measuring the voltage between terminal #4 (#A4) and ground terminals #16 (#A16) and #46 (#A46). The voltmeter should read battery voltage.

  Check that the fuse for the circuit is intact if the voltage is incorrect.

  If the fuse is blown, check the cable between brake control module terminal #4 (#A4) and the fuse. Check for a short-circuit to ground.

  If the fuse is intact, check the cable between brake control module terminal #4 (#A4) and the fuse. Check for an open-circuit.

  If no fault is found in the cable between brake control module terminal #4 (#A4) and the fuse, check the cable between the fuse and the ignition switch.

  Other information 

  • To connect the breakout box, see
  • For further information about the fuses and relays, see the Wiring Diagram.
  Fig 3: Breakout Box

  Courtesy of VOLVO CARS OF NORTH AMERICA.
  Fig 4: Identifying Voltmeter

  Courtesy of VOLVO CARS OF NORTH AMERICA.

Was a fault detected? 

• OK 

  Refer to Verification 

• NOT OK 

  Refer to Checking the 30-supply (valves) to the control module