Checking Communication Problems

Checking Communication Problems, S40/V40 Models







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 cables between data link connector (DLC) terminal #7 and the connected control modules. Check for an open-circuit. See Checking wiring and terminals - Permanent faults. Check for a short-circuit to ground. See Checking wiring and terminals - Permanent faults. Check for a short-circuit to supply voltage. See Checking wiring and terminals - Permanent faults.

Checking Wiring And Terminals

Communication cable for the cruise control as an independent system (not integrated)
- Check the communication cable between the data link connector (DLC) terminal #13 and the cruise control control module. Check the cable for an open-circuit, short-circuit to ground and a short-circuit to supply voltage according to the above references.

Communication cable for engine management system Fenix 5.1 and diesel (not Lucas)
- Check the communication cables between the data link connector (DLC) terminal #11/#15 and the engine control module (ECM). Check the cable for an open-circuit, short-circuit to ground and a short-circuit to supply voltage according to the above references.

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

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