ASE XEV1 key terms

Rubber gloves rated to withstand 1,000 volts AC and 1,500 volts DC, required whenever hands enter the high-voltage zone. They must be electrically retested on schedule and inspected before every use.

Rolling the cuff of an insulating glove to trap air inside, then checking for pinholes, cracks, or bulges. Performed together with a visual inspection before each use; a failed glove is removed from service.

Over-gloves worn outside the rubber insulating gloves to guard against cuts, abrasion, and punctures. They contribute no electrical insulation themselves and must be replaced when worn, stiff, or wet.

Hand tools with molded insulation rated to 1,000 volts and marked accordingly. They are used near high-voltage components, inspected for cracks before each use, and discarded once the insulation is damaged.

Rapid release of heat, light, pressure, and molten metal caused by an electrical fault through air. A shorted high-voltage pack or a stuck contactor can produce one, so face and hand protection are worn.

A safety classification such as CAT II, CAT III, or CAT IV showing how much transient overvoltage a meter and its leads can survive. High-voltage vehicle work requires at least CAT III equipment.

The current at which a shocked person's muscles contract so tightly they cannot release the conductor, roughly 10 to 16 milliamps of AC. Above that level the shock continues until the circuit opens.

A practice of having a second qualified person present whenever high-voltage work is performed, able to shut off power, call for help, or begin rescue if the technician is incapacitated.

Barricade tape, cones, or signs marking the area around a vehicle with an exposed or energized high-voltage system, keeping unqualified staff and customers out of the work zone.

Evacuate, call the fire department, and tell them a lithium-ion battery is involved. Cooling with large volumes of water is the usual approach; the pack can reignite hours later and needs monitoring.

Orange cable, conduit, and connector shells identify high-voltage circuits on most vehicles. Color is only a guide; confirm with service information and a meter before touching anything.

A manufacturer decal on the pack, cables, and covers stating the voltage present and warning that only qualified technicians should service the component. Labels are located and read during vehicle assessment.

A removable plug, lever, or switch that opens the high-voltage circuit and typically splits the pack into safer lower-voltage sections. Removing it is the first disabling step on many vehicles.

A low-voltage loop routed through high-voltage connectors and covers. When a connector is unplugged or a cover removed, the loop opens and the controller commands the main contactors to open.

Applying a lock and tag to the service disconnect or power source so the circuit cannot be re-energized by someone else while service is in progress. Only the person who applied it removes it.

Confirming a circuit is de-energized by testing the meter on a known live source, then the high-voltage points, then the source again, and reading near zero volts at every test point.

The interval after shutdown before inverter and converter capacitors bleed down to a safe voltage, often five to ten minutes. Wait the specified time, then measure instead of assuming.

The state the vehicle enters after the ignition is off, the key fob is moved away, and a waiting period passes, during which controllers stop communicating and contactors open. Required before disabling.

The high-voltage assembly of modules, busbars, electronics, and cooling hardware that stores and delivers energy to the drive motor. Also called the high-voltage or propulsion battery.

A group of individual cells connected in series and parallel and packaged together. Several modules are stacked inside the traction battery pack and are usually not serviceable on their own.

Controller inside the pack that measures cell voltages, temperatures, and pack current, balances cells, and reports state of charge and state of health to the rest of the vehicle.

A heavy-duty relay that closes to connect the battery pack to the high-voltage system when the vehicle is switched on and opens on shutdown or fault. Contacts can weld closed.

A resistor path that lets a small current fill the inverter capacitors before the main contactors close, limiting the inrush current that could otherwise arc and weld the contacts.

Power electronics that switch battery DC into three-phase AC to drive the motor and rectify the motor's AC output back into DC during regenerative braking.

A device that reduces high-voltage pack voltage to roughly 12 to 14 volts to run accessories and charge the auxiliary battery, replacing the alternator on many xEVs.

The component that converts AC power from the charge station into high-voltage DC to charge the pack, and communicates with the station through the charge port.

The electric machine that propels the vehicle, most using permanent magnets in the rotor. It also acts as a generator during regenerative braking and can produce voltage when spun by hand.

A rotor position sensor on the motor shaft that reports shaft angle to the inverter so phase currents are timed correctly. A faulty resolver causes poor torque or a no-start.

Using the drive motor as a generator so the vehicle's momentum charges the pack and slows the car, recovering energy that friction brakes would otherwise turn into heat.

A self-accelerating temperature rise inside a lithium-ion cell that spreads to neighboring cells and releases flammable gases and heat. It can start from damage, overcharge, or an internal short.

Equalizing the charge between cells in a pack, usually by slowly draining the higher cells, so the weakest cell does not limit usable capacity and driving range.

A scan tool function that lets the technician command modules, contactors, pumps, or fans to run for testing instead of only reading data and codes.

A snapshot of sensor and operating values recorded the moment a diagnostic trouble code set, showing the conditions under which the fault occurred.

A code or condition where high-voltage conductors leak current to the chassis through damaged insulation, moisture, or contamination. Measured with an insulation tester, often after disabling the system.

The battery management system's estimate of remaining pack capacity compared with when the pack was new, expressed as a percentage. Used to judge wear and warranty eligibility.

A dedicated hydraulic table with a flat, pack-sized platform used to lower and support high-voltage packs. Packs are heavy and must never be handled with a floor jack or improvised blocking.