If a communication diagnostic trouble code can be read from the control module, the malfunction is
probably intermittent. Intermittent fault in the voltage supply and ground to a control module on the CAN
network results in the Central electronic module (CEM) storing a diagnostic trouble code (DTC) for an
open-circuit in communication with the control module where the voltage supply does not work. There
will probably not be a diagnostic trouble code (DTC) in the control module where the open-circuit in the
voltage supply occurred as the control module cannot store a diagnostic trouble code (DTC) when it is not
supplied with power.
Fig. 1: View Of Control Module Block Diagram, Communications Network, And Trouble Codes
Courtesy of VOLVO CARS CORPORATION
Continue
Refer to
CHECKING RESISTANCE IN CAN-NET
CHECKING RESISTANCE IN CAN-NET
Fig. 2: Ignition Off And Disconnecting Battery Negative Lead
Courtesy of VOLVO CARS CORPORATION
Ignition off
NOTE:
Central electronic module (CEM) should not be replaced in case of CAN-
fault, unless troubleshooting reveals that Central electronic module (CEM)
has an internal fault.
2012 Volvo C30 T-5
ELECTRICAL Body Electrical
