Absence of bus communication (CAN5 buffer overflow)
شرح
The fault is validated as present if the ECU tries to send CAN-messages on CAN-bus 5, but no acknowledge is received from other unit(s), and thereby causing the internal buffer in the ECU to overflow. The DTC is set to active if the buffer overflow has lasted for 50 ms. The DTC is set to inactive when the CAN-messages are sent properly again and the buffer no longer is overflowing for the last 1050 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 • short circuit on CAN-bus 5 (separate DTC), except from short circuit between CAN-high and supply voltage
علت
• Defect connectors on ECU for CAN-bus 5 (pin B6 or B15). • Defect wiring for CAN-bus 5, open circuit on CAN-high (pin B6) or CAN-low (pin B15). • Ignition signal (pin A1) on the ECU is short circuit to supply. • Short circuit between CAN-high and supply voltage. • High busload • Defect ECU unit(s) on the CAN bus.
unconnected or shorted pins. Disconnect one ecu at a time.
