To me that means electrical, not mechanical. Means the handbrake switch works and haldex controller works, otherwise itd do nothing.I have to say, one fairly unique difference with your problem is that when you try the handbrake trick of lifting it up one notch then you never have a problem- 99% all rear locking wheel issues I have read stated that the handbrake trick did not work for them.
Surely that must mean something to an expert and it's a fundamental point on where the problem is.
Lifting the handbrake one notch tell the haldex unit not to activate the electronic controller. So i'd assume electrical too as the Haldex is engaged when it shouldn't beI have to say, one fairly unique difference with your problem is that when you try the handbrake trick of lifting it up one notch then you never have a problem- 99% all rear locking wheel issues I have read stated that the handbrake trick did not work for them.
Surely that must mean something to an expert and it's a fundamental point on where the problem is.
in vagcom could you run a test on the pump tho? and hear it prime itself etc etc
which year, engine model is your car ?
your fix is a first I've heard (pre charge pump failure) for this kind of issue.
especially wierd when you couple the specific problems you were experiencing - so it doesn't quite make sense that was the issue.