New-Vehicle Warranties Explained: What Bumper-to-Bumper, Powertrain and Corrosion Coverage Include

November 09 2026,

The warranty booklet usually goes straight into the glovebox on delivery day, still in its plastic sleeve, and stays there until something goes wrong. At that point, a common surprise surfaces: the “bumper-to-bumper” warranty didn’t cover the repair, or the powertrain warranty had already ended, or the coverage turned out to depend on the odometer as much as the calendar.

Most of that confusion comes from thinking of a warranty as one promise. It’s actually several layers, each covering a different group of parts for a different length of time, and each with its own exclusions. Across the brands sold at Carson Automotive Group’s dealerships, the terms differ considerably, so understanding how the layers fit together makes it easier to compare vehicles and to know what to expect years into ownership.

How Time and Distance Limits Work

Nearly every warranty term is written as a pair, such as three years or 60,000 km. Coverage ends at whichever comes first. A driver who covers long distances can reach the kilometre limit well before the time limit, while a low-mileage driver will usually run out of time first.

Some coverage is described as unlimited kilometres. That removes the distance ceiling only. The time limit still applies, so a five-year unlimited-kilometre warranty still ends after five years. The clock also starts earlier than many buyers expect: generally at the vehicle’s first retail delivery or first use, which is worth confirming on any vehicle that served as a demonstrator before sale.

Bumper-to-Bumper Coverage

The term “bumper-to-bumper” usually refers to a manufacturer’s basic or comprehensive new-vehicle limited warranty. It covers repairs needed because of defects in materials or workmanship across most of the vehicle, from electrical systems and climate control to many interior and exterior components.

The word “limited” matters. Basic coverage is about manufacturing defects, not every repair a vehicle might need. Routine maintenance, normal wear, accident damage and environmental damage fall outside it. Some items have their own, shorter terms. Ford, for example, covers brake pads and linings and a manual clutch disc for 12 months or 20,000 km under its wear coverage, rather than for the full basic term.

Powertrain Coverage

Powertrain coverage protects the components that make the vehicle move: listed parts of the engine, transmission and driveline. It typically lasts longer than basic coverage, which is why it often features prominently in comparisons.

The key word is “listed.” Powertrain coverage applies to the components named in the warranty booklet, not every part involved in driving the vehicle. A powertrain warranty that outlasts the basic warranty is valuable protection for the most expensive mechanical systems, but it won’t cover, say, a failed infotainment screen once basic coverage has ended.

Corrosion Coverage

Corrosion coverage is usually split into two kinds. Perforation coverage protects against rust that eats completely through a body panel, creating a hole. Surface corrosion, which doesn’t break through the metal, is handled under separate and usually shorter or more conditional terms. Perforation coverage is often the longest-running part of a new-vehicle warranty, frequently with unlimited kilometres, because rust-through takes years to develop.

Electrified Vehicle Coverage

Hybrids, plug-in hybrids and electric vehicles add another layer for their high-voltage components, such as the battery, inverter, onboard charger and electric drive parts. These terms tend to be long. Ford covers hybrid and electric unique components for eight years or 160,000 km, including qualifying high-voltage battery defects. Mazda covers the CX-90 PHEV’s high-voltage battery for the same eight years or 160,000 km. Mitsubishi covers the lithium-ion battery in its PHEV and EV models for 10 years or 160,000 km.

Defect coverage and capacity loss are different things. A battery warranty covers manufacturing defects, but the gradual loss of capacity that comes with age is treated separately, and the rules for it vary by brand and model. The specific vehicle’s booklet is the place to confirm both.

How the Brands Compare

The headline terms show how differently the four brands in the group approach coverage:

Brand	Basic Coverage	Powertrain Coverage
Ford	3 years or 60,000 km	5 years or 100,000 km (diesel: 5 years or 160,000 km)
Mazda	3 years, unlimited km	5 years, unlimited km
Mitsubishi	5 years or 100,000 km	10 years or 160,000 km
Land Rover	4 years or 80,000 km	Included within the 4-year or 80,000 km coverage

Corrosion terms differ as well. Ford covers perforation for five years with unlimited kilometres, including qualifying aluminum body panels. Mazda’s anti-perforation coverage runs seven years with unlimited kilometres. Land Rover covers corrosion perforation for six years with unlimited kilometres.

Roadside assistance follows its own schedule too: five years or 100,000 km with Ford, three years with unlimited kilometres with Mazda, five years with unlimited kilometres with Mitsubishi, and four years or 80,000 km with Land Rover. Mazda also allows remaining factory coverage to transfer to a subsequent owner at no charge, once the new owner submits a notification.

What Warranties Don’t Cover

Every warranty excludes certain things, and knowing them avoids surprises. The common exclusions include:

Scheduled maintenance, such as oil changes, filters and tire rotations
Normal wear, beyond any specific wear coverage the brand provides
Damage from accidents, the environment or road hazards
Damage caused by misuse, alterations, the wrong fluids or skipped maintenance

That last point is often misunderstood. Under Ford’s terms, damage caused by misuse or improper maintenance invalidates coverage on the parts affected, not automatically on every unrelated part of the vehicle. Still, following the model’s maintenance schedule and keeping records matters. Mazda’s owner documentation, for example, advises keeping maintenance records, receipts and repair orders and presenting them if a coverage question ever comes up.

Extended Protection Plans

Each brand also sells optional plans that extend or supplement factory coverage: Ford Protect service contracts and maintenance plans, Mazda Added Protection, Mitsubishi Diamond Care Mechanical Breakdown Protection, and the Land Rover Vehicle Protection Plan. These are separate contracts, not part of the factory warranty, and they differ in which components they cover, how long they last, whether a deductible applies and whether they transfer to a future owner.

Before adding one, it’s worth comparing its coverage against what the factory warranty already provides, so the plan pays for protection that doesn’t overlap. Reading the contract’s list of covered parts, the term, and the exclusions is the best way to judge its value.

Reading the Layers Together

A new-vehicle warranty works best when it’s read as a set of overlapping protections: basic coverage for most defects in the early years, powertrain coverage for the major mechanical systems, corrosion coverage for rust-through over the long term, and electrified coverage for high-voltage parts. Each layer starts at the same moment and ends on its own schedule.

The sales and service teams at Carson Automotive Group’s dealerships can walk through the specific warranty booklet for any vehicle a buyer is considering, with every location listed on the group’s website.