Closed Circuit Current Draw Testing: Notes

Increased closed-circuit currents may occur permanently or intermittently and cause the battery to discharge prematurely. The increase in closed circuit current may be caused by a faulty control unit or by the installation of a non-approved accessory.

Minimal amounts of parasitic draw can be overcome by the chemical reaction that takes place inside the battery. A problem occurs when the average vehicle current consumption higher that the battery can produce chemically.

In a situation where a vehicle has broken down due to a discharged battery, for diagnostic purposes it is important not to disconnect the battery. The control unit may reset if the battery is disconnected. Following a reset, a faulty control unit may start functioning correctly again, making accurate diagnosis impossible.