Glossary of Automotive Terms - P

Click on any letter to find automotive-related entries beginning with that letter.


Actually, PPG Industries, founded in 1883 as the Pittsburgh Plate Glass Company. PPG has been the source of tough urethane finishes on cars racing in the Indianapolis 500 since 1975. In 1980, it became the title sponsor of the PPG Indy Car World Series.


Professional Racers Organization


Acronym for pounds per square inch. A pressure measurement used in tire inflation and turbocharger boost.

Pace Car

Seen at NASCAR and Indy races, the pace car leads race cars out of the pole position at beginning of races or after a yellow flag or restart has been called.

Package Shelf

The ledge between the rear seat and the backlight (or rear windshield). The name is misleading because it's a bad idea to put anything on the package shelf. However, it often contains the sound system's rear speakers and, on some vehicles, the CHMSL or center brake light. Sometimes also called the package tray. On European cars the package tray often contains a first-aid kit; on higher-end models it may contain storage compartments.

Papers of Origin

Manufacturer documents used to obtain vehicle titles.

Partial Loss

Any loss that does not completely destroy the property or exhaust the insurance.

Passive Restraint

A device or structure that automatically helps restrain vehicle occupants in an impact. This includes airbags, belt pretensioners, padded knee bolsters, and shoulder belts that are motorized, or attached to the door.


A cause of a possible loss.

Personal Injury Protection (PIP)

A broad type of medical payments insurance. Usually offers protection for expenses incurred up to a dollar amount.

Physical Damage

A generic term that describes injury or damage to property.

Physical Hazard

The material of the risk itself.


The type of truck with an open cargo bed behind the closed cab.


A type of gear that has small teeth that mesh with other, larger gears.


The heavy, cylindrical metal shaft within each engine cylinder that travels up and down to turn the crankshaft, compress the air and fuel mixture for combustion and expel exhaust gases.

Policy Period

The amount of time that the policy covers (i.e., six months or two years).


The person who has possession of the policy.

Positive Crankcase Ventilation Valve

An emission device that routes oil pan vapors to the intake manifold to be burned during combustion. Also known as the PCV valve.

Positive Equity

The vehicle's market value is greater than the amount the borrower owes on it.

Power Plant

Another name for a vehicle's engine.

Power Steering

A steering system that uses a separate motor or engine power to reduce the effort necessary to turn the front wheels.

Power-to-Weight Ratio

The maximum power output of the vehicle per unit mass. The higher the ratio, the more powerful the vehicle. In comparing several vehicles, this can be a better measurement than engine horsepower or torque because it considers the weight variable. In other words, a car that seems to have a powerful engine but is also heavy may have less get-up-and-go than a vehicle that has a similar or less powerful engine but also weighs less.


The combination of engine and transmission.


The periodic payment to keep the policy enforced.

Preparation Charges

Charges incurred by the dealer while preparing a vehicle for delivery to the buyer.

Pressure Plate

Holds the clutch disc against the flywheel.


A device that rapidly yanks in shoulder-belt slack when a crash sensor detects an impact. Some pretensioners are activated by a small explosive charge in the belt retractor; some contain their own inertial sensors. So far, pretensioners are still found on more expensive models, particularly those by European manufacturers. By pulling in belt slack within milliseconds of an impact, pretensioners help reduce chest and head injury by restricting occupant motion and preventing the occupant from hitting the belt.

Pro Rallies

Road rallies which are very competitive and are run at high speeds on roads closed to the public. Often sponsored by the SCCA.

Pro Start

A method of starting a drag race that differs from most starts in that it only has one amber light between the initial staging and the final lights on the "Christmas Tree."

Projector-Beam Headlights

A headlight that uses a spherical reflector to tightly control the light beam. The bulb or light source directs the light inward, toward the reflector at the back of the headlight assembly, which then projects it forward from the vehicle. These lights are more powerful, accurate and expensive than standard sealed-beam and halogen headlights, and are generally found on sport and luxury models.

Proof of Loss

A formal statement made by the insured to the insurance company regarding a loss.

Property Damage Liability

The protection of the property when not under control of the insured.

Purchase Option

The lessee's right to purchase the vehicle, if he so chooses, at lease end. It's a good idea to negotiate a purchase-option price at the same time you negotiate the capitalized cost and residual value, if possible. Some contracts lock-in a pre-determined value for the vehicle.


A metal rod that transmits the motion of the camshaft to the valve actuators to open and close the valves. Used on engines with overhead valves but without overhead camshafts.

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Glossary of Automotive Terms P - Autotrader