The present invention provides a method of electrochemically measuring a hematocrit value using a sensor, capable of achieving excellent measurement accuracy and reliability and also provides a sensor used in the method. First, a substrate with a silicon-containing photo resist layer thereon is provided. A novel electric power steering controller has a relay contact voltage detection means and a discharging circuit. The second powertrain includes the electric traction motor and it is coupled with a second set of road wheels.