BDU relay fault
• Check the VCB main fuse located in the maintenance disconnector mounted in the battery pack (E83). • Measure the resistance over the fuse. If open load change the fuse. • Change the BDU according to multi instruction and reset the relay counter via SDP3. NOTE! Replacing the BDU is considered an electrical work and shall only be performed by Scania certified personnel. Vehicle shall be made safe according to electrical work procedure. • If fuse is OK perform the following steps: • Dismount the battery according to multi instruction • Check the connectors to the IBU according to multi instruction for IBU • Check the 24V-connector to the BDU according to multi instruction for BDU • Change the IBU according to multi instruction NOTE! Replacing the IBU is considered an electrical work and shall only be performed by Scania certified personnel. Vehicle shall be made safe according to electrical work procedure.
What you'll see
No driver-visible symptom recorded.
System reaction
• VOR, the hybrid system will not work since the battery will not be engaged. The DCC will not receive VCB-power and the 24-volt system will drain the 24-volt batteries. • Amber warning lamp "24V batteries not charged" and "Hybrid System Fault" is shown in ICL
Diagnostic depth
The BMU(E81) will set a DTC based on the error flags that are sent from the IBU
•Contactors operated during high load •Bad connector in IBU •Bad connector in BDU •Driver in IBU is broken •Broken relay coil