Figure 8: Hybrid Electric (HEV), Pluggable HEV, Regular and Extended Ranged Electric Vehicle (EV) all use high voltage battery packs and power electronics (inverters and DC-DC converters) that produce heat. On some vehicles such as the Chevrolet Volt, the High Voltage (HV) Li-Ion battery pack produces enough heat to justify a sophisticated thermal management system. The system utilizes a liquid cooling system that uses the same p/n GM DEX-COOL 50-50 premix as the Internal Combustion Engine (I.E.C.). If the coolant contains even minor amounts of inorganic ions (conductive minerals from the soil that dissolve in water) the chances for a HV leakage DTC or worse yet an actual short within a component cooled by coolant, the HEV / EV will NOT run. This means true Demineralized / Deionized (DI) water must be used, not well water, city water or even distilled water if you mix your own antifreeze / water opt out of pre-mix that uses DI water. May 2017 5 MACS Service Reports