you will do much better to ask this forum. did it once in anger and it was not a good experience but I was very frustrated. looking for confirmation from many points of view. The end all was that a bus engine
had a heat problem with the pcu. I wanted someone to confirm that what i saw was right. My gut said I as right the information said I was right but 2 shops kept trying to persued me I should seek a different path. That was asking a bit much. A great deal of time and energy confirmed the PCU but ask.com was useless. My gut was better wish I had asked this forum what they thought.