Volvo C30 2007 Service And Repair Manual page 313

Faults in the CAN network may be due to a control module sending faulty messages that disrupt normal
communication. When messages are sent incorrectly, this results in a considerable increase in the amount
of traffic on the CAN network. The load can be checked by reading the average value of the voltage on
the CAN cables in relation to ground.
Measure voltage between the following connections on the OBDII-box/diagnostics socket.
#3 and #4 (ground). The voltage should be approx:2, 8 - 3, 2 V.
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#11 and #4 (ground). The voltage should be approx:1, 8 - 2, 2 V.
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#3 and #11. The voltage shall be between approx. 0.55-1.4 V. The voltage shall normally be
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between 0.55 - 0.90 V. A higher voltage may indicate increased traffic on the CAN-net. In case of
fault in communication/too high traffic on the CAN-net, the voltage is considerably higher than the
above stated values.
NOTE: After fault with control modules that interfere with communication, other
control modules may remain in Limp-Home even when the ignition has
been turned off and on a few times. For certain faults in the CAN-net where
control modules have stopped communicating, it may help to
disconnect/reconnect the battery to "restart" the control module/CAN-net.
HINT: DiCE can be used as fault detection tool if fault is suspected on the CAN-net that cannot be
detected with normal troubleshooting. Interference, intermittent faults, faulty messages on the
CAN-net etc., are examples of such faults. The tool registers fault messages used on the CAN-net.
Fault messages may be caused by short intermittent malfunctions on the CAN-net or by a control
module sending fault messages. See tools:951 3010 as well as associated TJ 20402.
Ignition on.
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Connect DiCE to the diagnostics socket.
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Note the blue LED-indicator. The indicator flashes to show detection of fault messages.
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NOTE: Certain interference may occur without any real fault
Cable fault
Shake the cables lightly and pull lightly on the connections during the check to locate any fault.
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Note the blue LED-indicator.
"Chatting" control modules
"Chatting" control modules may be difficult to find and troubleshooting may take time. Let the
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vehicle stand with DiCE connected for an extended time period. Afterwards, activate functions to
provoke a malfunction. It may take up to several hours before the fault messages are sent. When the
indicator starts to flash, remove the fuse for one control module at a time until the indicator stops
flashing. When the indicator stops flashing, restore the fuse for the relevant control module and
check that the indicator starts to flash again. Then it is likely that the problem is identified.
2012 Volvo C30 T-5
ELECTRICAL Body Electrical