Mercedes A class, testing rear brakes. The old VSI stated you had to test them with engine off, ignition on, charging the servo before testing each wheel. This is backed up by info from elsewhere. Today’s advice is they must be tested with the ignition off. I have no trust in their accuracy now.I also notice quite a few models having a warning about high voltage at various points around the vehicle as if it were a hybrid, when it’s not.
