Absence of Auxilliary CAN bus communication (CAN2 buffer overflow)
• Check connector for Auxilliary CAN-bus on CUV (pin C35 and pin C36). • Check wiring for Auxilliary CAN-bus: - Measure the resistance (with the battery disconnected) between CAN-high (pin C35) and CAN-low (pin C36). 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 CUV (pin C35) and CAN-high on any other unit on the Auxilliary CAN-bus. It should be close to zero ohm. - Measure the resistance (with the battery disconnected) between CAN-low on CUV (pin C36) and CAN-low on any other unit on the Auxilliary CAN-bus. It should be close to zero ohm. • Check wiring and connector for the ignition signal (pin C24) on the TBD.
What you'll see
No driver-visible symptom recorded.
System reaction
• Visibility warning is aktive • Lowbeam and position light is turned on as safety light • Functions dependent on information on the Auxilliary CAN-bus from CUV might be degraded.
Diagnostic depth
Communication error. Auxilliary CAN-bus buffer overflow. The Auxilliary CAN-bus has an open circui or short circuit to 24V or ground.
• Defect connectors on CUV for Auxilliary CAN-bus (pin C35 or pin C36). • Defect wiring for Auxilliary CAN-bus, open circuit on CAN-high (pin C35) or CAN-low (pin C36). • Ignition signal (pin C24) on CUV is short circuit to supply.