Electrical error on Yellow bus (CAN2 BusOff)
• Measure the resistance (with the battery disconnected) between CAN-high (pin B2) and CAN-low (pin B11). 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 B2) and supply. It should be high ohmic (Mega ohm). • Measure the resistance (with the battery disconnected) between CAN-high (pin B2) and ground. It should be high ohmic (Mega ohm). • Measure the resistance (with the battery disconnected) between CAN-low (pin B11) and supply. It should be high ohmic (Mega ohm). • Measure the resistance (with the battery disconnected) between CAN-low (pin B11) and ground. It should be high ohmic (Mega ohm). • Disconnect one ECU unit at a time from the yellow 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. Disconnect one ecu at a time.
What you'll see
• Several warnings are active in the instrument cluster. • Functions dependent on information from yellow CAN bus are degraded. Examples listed below. - engine speed display in the instrument cluster. - engine speed display in the instrument cluster. - direction indicator tell-tales in the instrument cluster.
System reaction
Red COO Stop Lamp
Diagnostic depth
Communication error. The CAN-controller of the yellow CAN-bus has entered state bus-off. There might be a short circuit on the yellow CAN-bus
• Defect wiring of yellow CAN-bus: - 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 unit(s) on the yellow CAN-bus. • ECU unit(s) on the red CAN-bus communicates with 250 kb/s. • These causes might not be detectable by the CAN controller. Instead timouts will occur for involved ECUs.