Current sensor current out of range
• Turn off and lock the interlock loop control switch S229. Read Insulation Fault Status with SDP3. Perform visual inspection of VCB cables, if damaged cable found replace cable according to spare part. NOTE! Replacing of cables and fault tracing from here on is considered an electrical work and shall only be performed by certified personnel. Vehicle shall be made safe according to electrical work procedure. • Turn off U30 and remove ignition key. Remove the flange with cable fittings that connects to the MGU from the VCB central electric unit P7 according to instruction in multi. Perform manual resistance measurement between positive and negative terminal in the VCB central electrical unit(P7). Repeat measurement between positive and negative VCB ring connectors on the flange to the MGU to distinguish whether the fault is present on the MGS side or in the HRU/HPU. • To further trace fault disconnect all VCB cables and perform manual measurement on each respective cable, then on each respective component until fault is traced. Replace faulty component according to spare part plan. • If the fuse has burned, dismount the battery pack (E83) according to instruction in multi • Change BDU mounted in battery pack (E83) according instruction in Multi • Reset the relay counters in the IBU according to instruction in Multi • Change the fuse in the maintenance disconnector mounted in battery pack (E83) according instruction in Multi 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.
What you'll see
No driver-visible symptom recorded.
System reaction
• Depending on the severity of the short circuit it will either be handled by the BDU or the fuse. Uncontrolled currents in the range from 450A to 950A are interrupted by the BDU. Currents above 950A are interrupted by the fuse. Currents below 450A are not handled unless any safety limit of the battery is reached such as cell voltage and cell temperature limits. After a short circuit it will not be possible to start the system, it will generate DTC(0277 PreCharge error 0262 BDU rely fault) • 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
If below the fuse shut off current (<950A) the fault will be detected by the battery pack current sensors. If >950A the battery pack fuse will interrupt the circuit. In both cases amber warning will be shown in ICL.
Short circuit within the VCB electrical system.