Absence of CAN bus 5 communication
• Trouble shoot CAN bus 5 cable harness and connectors. • Check connector for CAN-bus 5 on MBS. • Check wiring for brown CAN-bus: - Measure the resistance (with the battery disconnected) between CAN-high and CAN-low. It should be close to 60 ohm (one 120 ohm termination resistor in each end of the CAN-bus). - Measure the resistance (with the battery disconnected) between CAN-high on MBSM and CAN-high on any other unit on CAN bus 5. It should be close to zero ohm. - Measure the resistance (with the battery disconnected) between CAN-low on MBS and CAN-low on any other unit on CAN bus 5. It should be close to zero ohm.
What you'll see
If equipped with electrical roof hatches or a HPAC, those may not work as intended.
System reaction
Functions dependent on information from CAN bus 5 are degraded/missing in MBS (Master)
Diagnostic depth
The fault is validated as present if the ECU does not detect CAN-messages on CAN bus 5 within the timeout period
• Defect wiring for CAN bus 5. • Defect ECU unit(s) on CAN bus 5.