Electrical error on CAN-bus 3 (CAN3 BusOff)
• Measure the resistance (with the battery disconnected) between CAN-high (pin B3) and CAN-low (pin B12). 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 (pin B3) and supply. It should be high ohmic (Mega ohm). • Measure the resistance (with the battery disconnected) between CAN-high (pin B3) and ground. It should be high ohmic (Mega ohm). • Measure the resistance (with the battery disconnected) between CAN-low (pin B12) and supply. It should be high ohmic (Mega ohm). • Measure the resistance (with the battery disconnected) between CAN-low (pin B12) and ground. It should be high ohmic (Mega ohm). • Disconnect one ECU unit at a time from the CAN-bus and check if the fault disappears. • Check connector pins • Check cabling • Check connectors for all ECU:s on the indicated bus. Check for verdigris, broken, unconnected or shorted pins.
What you'll see
* Prohibit side assistance (Shutdown BSW, LCP, and VRUD).
System reaction
• Warnings may be active in the instrument cluster (dependent on vehicle configuration). • Functions dependent on information from SRR Left Side are degraded.
Diagnostic depth
The DTC is set to active if CAN controller of CAN-bus 3 is in the state bus-off. The DTC is set to inactive if the CAN-controller is not in state bus-off for 1100 ms. The DTC is not validated (stored) if: • the ignition is turned off • first 2 seconds after ignition on • the supply voltage is below 22 volt • the supply voltage is above 32 volt
• Defect wiring of CAN-bus 3: - CAN-high interrupted - CAN-low interrupted - CAN-high and CAN-low interrupted at the same location - Loss of connection to termination network - short circuit between CAN-high and CAN low. - short circuit between CAN-high and supply voltage. - short circuit between CAN-high and ground. - short circuit between CAN-low and supply voltage. - short circuit between CAN-low and ground. • Defect ECU on CAN-bus. • ECU on CAN-bus communicates with 500 kbps. • These causes might not be detectable by the CAN controller. Instead timeouts will occur for involved ECUs.