Checking connectors and bus wire
Remember that the CAN network is only a communications network. There are therefore no fuses, switches and sensors on the CAN bus. Check the resistance as described below (see reference).
To maintain the correct values the battery should be disconnected when measuring resistance.
Check the bus wire for a short circuit to ground as described in Short-circuit to ground, intermittent faults .
Also check the intermediate connectors for contact resistance and oxidation as described in Contact resistance and oxidation and for a loose contact as described in Loose connections (terminals) .
HINT: If the fault is found before all the wires below have been checked trouble-shooting is not necessary on the wires.
The following wires and connectors should be checked to locate the short circuit.
Wire between:
- road traffic information module (RTI) 22A and rear electronic module (REM) 17A.
road traffic information module (RTI) 10A and rear electronic module (REM) 15A.
To connect the test box to the RTI control unit, see Connecting breakout box, Road Traffic Information (RTI) control module
To connect the test box to the REM control unit, see Connecting the breakout box
- rear electronic module (REM) 16A, driver information module (DIM) 9 and intermediate connector 54/40.
rear electronic module (REM) 14A, driver information module (DIM) 8 and intermediate connector 54/40.
To connect the test box to the REM control unit, see Connecting the breakout box
To connect the test box to the DIM control unit, see Connecting the Driver Information Module (DIM) test box
- central electronic module (CEM) 2D and driver information module (DIM) 9.
central electronic module (CEM) 3D and driver information module (DIM) 8.
To connect the test box to the CEM control unit, see Connecting the breakout box
To connect the test box to the DIM control unit, see Connecting the Driver Information Module (DIM) test box
- power seat module (PSM) 3B and driver information module (DIM) 9.
power seat module (PSM) 2B and driver information module (DIM) 8.
To connect the test box to the PSM control unit, see Connecting the breakout box, power seat module (PSM)
To connect the test box to the DIM control unit, see Connecting the Driver Information Module (DIM) test box
- driver information module (DIM) 3 and climate control module (CCM) 12A.
driver information module (DIM) 2 and climate control module (CCM) 14A.
To connect the test box to the DIM control unit, see Connecting the Driver Information Module (DIM) test box
To connect the test box to the CCM control unit, see Connecting the breakout box
- audio module (AUM) 8A and climate control module (CCM) 12A.
audio module (AUM) 7A and climate control module (CCM) 14A.
To connect the test box to the AUM control unit, see Connecting the breakout box, Audio control module
To connect the test box to the CCM control unit, see Connecting the breakout box
- phone module (PHM) 10A and climate control module (CCM) 12A.
phone module (PHM) 22A and climate control module (CCM) 14A.
To connect the test box to the PHM control unit, see Connecting breakout box, carphone module
To connect the test box to the CCM control unit, see Connecting the breakout box
- passenger door module (PDM) 3A, climate control module (CCM) 12A and intermediate connector 54/11.
passenger door module (PDM) 2A, climate control module (CCM) 14A and intermediate connector 54/11.
To connect the test box to the PDM/DDM control units, see Connecting the breakout box
To connect the test box to the CCM control unit, see Connecting the breakout box
- climate control module (CCM) 11A and steering wheel module (SWM) 19.
climate control unit (CCM) 13A and steering wheel module (SWM) 9.
To connect the test box to the CCM control unit, see Connecting the breakout box
To connect the test box to the SWM control unit, see Connecting the breakout box
- steering wheel module (SWM) 20 and supplemental restraint system (SRS) 25B.
steering wheel module (SWM) 10 and supplemental restraint system (SRS) 23B.
To connect the test box to the SWM control unit, see Connecting the breakout box
To connect the test box to the SRS control unit, see Connecting the breakout box
- supplemental restraint system (SRS) 26B, upper electronic module (UEM) 5 and intermediate connector 54/13.
supplemental restraint system (SRS) 24B, upper electronic module (UEM) 3 and intermediate connector 54/13.
To connect the test box to the SRS control unit, see Connecting the breakout box
To connect the test box to the UEM control unit, see Connecting the breakout box
- driver door module (DDM) 3A, upper electronic module (UEM) 5 and intermediate connector 54/10.
driver door module (DDM) 2A, upper electronic module (UEM) 3 and intermediate connector 54/10.
To connect the test box to the DDM/PDM control units, see Connecting the breakout box
To connect the test box to the UEM control unit, see Connecting the breakout box
Additional information:
- The voltage should be between approximately 1.5 V and 3.5 V.
- To disconnect the battery, see Battery, disconnecting .