This function is used to drain the SCR systems of AdBlue.
Normally a draining of the system is performed when the key is turned to OFF position, but some vehicles are equipped with delayed draining to reduce startup time during short stops.
The test can be used before service which requires that the SCR system is opened.
Test conditions:
Battery voltage above 20V.
Parking brake applied.
Engine off.
Procedure:
Start the function.
Check test conditions.
The system is drained.
The function is done.
If the function fails, check the test conditions and repair any faults.