IBU relay wear high set due to an unexpected IBU reset or loss of supply.
• If the DTC was set during a sudden loss of U30 during service with the engine at idle or paused and for some reason the U30 supply is broken and one can be certain that the current in the system was low. i.e. the vehicle speed is zero perform the following steps • Check that the 24 Voltage battery and the 24V electrical system in general is in good condition. • When good status of the 24 V system is assured run the service routine "Restore IBU relay contactors" to restore the value to the last known value with SDP3. • If the DTC was set during a sudden loss of U30 during driving and one cannot be certain that the current in the system was low during interruption perform the following step. • Change the BDU according to instruction in multi and reset the relay counters with SDP3.
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 DTC is set if the BMU suddenly losses supply and the IBU sets the relay wear high error flag.
This error code is set for safety reasons if the internal battery control unit (IBU) unexpectedly looses supply when the hybrid system is enabled. The reason is because the IBU cannot know the current amplitude during the opening of the contactors and the contactors may be opened with high current when this happend.