Checking Communication Faults

Checking communication faults, model V70 2000-, S60 and S80







Hint: For current information about the relevant circuit and signals, see the wiring diagram and signal specification for each system.

Data Link Connector (DLC)
- Check the power Supply to the Data Link Connector (DLC) terminal #16. The voltage must be approximately battery voltage
- Check the cable for power ground and signal ground to the Data Link Connector (DLC) terminals #4 and #5.

Hint: When the VCT2000 is connected to the Data Link Connector (DLC) (is powered up) the indicator LED lights green. The indicator LED then flashes during communication with a control module. In the event of certain internal faults, the VCT2000 indicator LED will be red!

Communication cables
- Check the communication cable between the Data Link Connector (DLC) terminal #7 and Central Electronic Module (CEM) terminal #D6 and with other connected control modules.
- Check for an open-circuit.
- Check for a short-circuit to ground.
- Check for a short-circuit to supply voltage.


CAUTION
If there is a fault in the communication cable, it will not be possible to establish communication on either the low or high speed network. The first time there is communication on this cable, the low and high speed network cables are connected between the Data Link Connector (DLC) and Central Electronic Module (CEM) to the other network in the car. This is controlled via a relay in the Central Electronic Module (CEM).



- For communication problems with control modules on the high speed network, check the communication cables between Data Link Connector (DLC) terminals #6 and #14 and Central Electronic Module (CEM) terminals #137 and #138.

- For, communication problems with control modules on the low speed network, check the communication cables between Data Link Connector (DLC) terminals #3 and #11 and Central Electronic Module (CEM) terminals #1319 and #1320. Check these cables for an open-circuit, a short-circuit to ground and a short-circuit to supply voltage

- Also check the communication cables for the low and high speed networks between the Central Electronic Module (CEM) and the other connected control modules.

Control modules
- Check that the control module power supply and ground terminal are fault-free.


CAUTION
If none of the above checks help, try Reading the Diagnostic Trouble Codes (DTCs) in the central electronic module. This is carried out via VIDA vehicle communication.


VCT2000 and wiring
- Try new wiring and/or a new VCT2000 if no faults are detected after the above fault-tracing.

Fault-tracing information
Falut-tracing communication problems is now finished.