IGNITION COIL- Device used to produce the high voltage needed for ignition spark.

IGNITION COMPUTER- ECM that controls ignition timing, based on sensor input.

IGNITION DISTRIBUTOR- Component that directs coil voltage to each spark plug at the appropriate time.

IGNITION RESISTOR- A resistance connected into the primary circuit to reduce battery voltage to the coil during engine operation.

IGNITION SWITCH- The switch in the ignition system that opens and closes the ignition-coil primary circuit.

IGNITION SYSTEM- Components that produce a spark to ignite the air-fuel mixture in the engine.

IGNITION TIMING- How early or late the spark plugs fire in relation to piston position.

IMPELLER- Pump component with fanlike blades that spins inside a housing to move liquid.

INCORRECT CAMBER- Condition that produces wear on one side of the tire tread.

INCORRECT TOE- Condition that produces a feathered edge on the tire tread.

INDEPENDENT SUSPENSION- System that permits each wheel to move up and down without seriously affecting any other wheel.

INFLATION PRESSURE- The amount of air pressure that a tire can safely handle.

INLET STUB SHAFT- Section of front drive axle that is splined to differential gears. It is connected to the interconnecting shaft through a universal joint.

INPUT- The information provided to a computer by a sensor.

INPUT SHAFT- Metal shaft that transfers motion from the engine (via the clutch) to the trans-mission.

INSULATED CURRENT RESISTANCE TEST- Check of all parts between the battery positive and the starting motor for excess resistance.

INSULATOR- A material that resists the flow of electrons.

INTEGRAL POWER STEERING- A system in which the hydraulic piston is mounted inside the gearbox.

INTEGRAL REGULATOR- A regulator that is mounted in or on an alternator.

INTEGRATED CIRCUIT- A tiny "chip" of silicon, containing complete electronic circuits.

INTERCONNECTING SHAFT- Component of front drive axle that connects the inner and outer universal joints.

JOUNCE BUMPER- Rubber blocks that keep suspension parts from hitting the frame when the vehicle encounters large bumps or holes.

JUMPS OUT OF GEAR- A manual transmission problem in which the transmission will unexpectedly disengage and move into neutral.

JUMP STARTING- Providing current to a vehicle with a dead battery by connecting cables to the battery of an operating vehicle.

KICKDOWN VALVE- Component that causes an automatic transmission to shift down into a lower gear during fast acceleration.

KNUCKLE- A steering knuckle; a front suspension part that acts as a hinge to support a front wheel and permit it to be turned to steer the vehicle.

LATERAL RUNOUT- Side-to-side movement of a wheel or tire.

LEAF SPRING- Flat pieces of spring steel that are stacked and bound together. Normally used as a part of the rear suspension of the vehicle.

LIMITED SLIP DIFFERENTIAL- One that provides driving force to both rear wheels at all times.

LIMITED SLIP DIFFERENTIAL CHATTER- Sound made when turning a comer, caused by sticking and releasing of clutches in the differential.

LINER- Thin rubber layer bonded to plies and forming the inside surface of the tire.

LOAD RATING- The maximum amount of weight a tire can carry when inflated to the recommended pressure.

LOCKED IN GEAR- A manual transmission problem often caused by damaged or sticking linkage. Broken gear teeth can also be at fault.

LOCKING HUB- Components that transfer power from the driving axles to driving wheels on a four-wheel drive vehicle.

LOCK-UP CONVERTER- A variation of the fluid coupling with an internal friction clutch mechanism. It "locks up" in high gear, improving fuel economy.

LOW BRAKE PEDAL- Farther than normal brake pedal travel before braking begins.

LUG NUT- Large steel nuts, used to hold a wheel into the axle hub.

LUG STUD- Special bolts that are press-fit into the axle hub and accept lug nuts to mount the wheels of the vehicle.

MACPHERSON STRUTE- Suspension system that uses one control arm and one strut for each wheel.

MAGNETIC FIELD- Field of force generated around an electrical conductor.

MAGNETIC SENSOR- One that uses part movement (such as rotation) and induced current to produce a signal for a computer.

MAIN COMPUTER- The largest and most powerful microprocessor in a system of the vehicle.

MAINTENANCE-FREE BATTERY- One without removable filler caps that does not require periodic filling with water.

MANUAL BLEEDING- A method of system bleeding using only the master cylinder.

MANUAL TRANSAXLE- One with a manual (driver-operated) transmission.

MANUAL VALVE- In an automatic transmission, a valve actuated by the gearshift lever that routes oil pressure to the components required for the selected gear.

MASTER CYLINDER- Hydraulic piston type pump that develops pressure for the braking system.

MILKY FLUID- Condition caused by contamination of transmission fluid by engine coolant.

MINIMUM DISC THICKNESS- Thinnest rotor dimension allowed for proper and safe operation of disc brakes.

MOVABLE POLE SHOE- Device that uses a yoke lever to move the pinion gear into contact with the flywheel.

MULTIPLE DISC CLUTCH- One with several discs that can be used to drive planetary gearsets.

MUSHY SHIFT- Transmission changes too slowly.

NEUTRAL SAFETY SWITCH- Switch that prevents engaging the starter when the vehicle is in gear.

NEUTRAL SAFETY SWITCH ADJUSTMENT- Altering position of the switch to permit starting of the engine when gear selector is in the PARK position.

NONDRIVING HUB- One that rotates freely on spindles (axle ends).

NONINDEPENDENT SUSPENSION- System in which wheels are attached to each end of a solid axle.