Checking The Control Module For Open-Circuits

Fig 1: Identifying Ignition ON

Courtesy of VOLVO CARS CORPORATION

• Ignition off
• Remove relay 2/158
• Ignition on.

  Check the driver circuit for the relay coil for an open-circuit as follows: activate the relay driver. Measure the voltage between terminals #1 and #2 on the relay base.

  The voltage between terminals #1 and #2 should be battery voltage.

  If the value deviates excessively, check the voltage between terminal #2 and the battery voltage and between terminal #1 and ground. Both should equal battery voltage.

  HINT: Do not forget to check that the power supply to the control module is OK. 

  Other information 

  • see CHECKING WIRING AND TERMINALS .
  Fig 2: Identifying VCT2000 Diagnostic Tool Symbol In VIDA

  Courtesy of VOLVO CARS CORPORATION
  Fig 3: Identifying Relays

  Courtesy of VOLVO CARS CORPORATION

Was a fault detected? 

• YES 

  Refer to VERIFICATION 

• NO 

  Refer to CHECKING THE CONTROL MODULE FOR SHORT-CIRCUITS