GLOSSARY

Lemon Law and Car Glossary

The legal words that decide a claim, and the mechanical ones that describe what actually went wrong.

Short answer

A lemon law claim turns on a handful of defined terms: what counts as a substantial defect, what a reasonable number of repair attempts means, and how long the vehicle was out of service. It also turns on describing the fault accurately, which is why the mechanical terms matter as much as the legal ones. All 99 are defined below.

99 terms

Your claim

Breach of warranty: A failure to honour the terms of a warranty, either by refusing a covered repair or by failing to complete one successfully. Read more See also Manufacturer's warranty Substantial defect Magnuson-Moss Warranty Act
Buyback: A repurchase. The manufacturer takes the vehicle back and returns what you paid, which generally covers the down payment, the payments made and the remaining loan balance, less a mileage offset. Read more See also Mileage offset Cash and keep Lemon title
Cash and keep: A settlement where you keep the vehicle and the manufacturer pays a sum for the diminished value. It is one of several possible outcomes rather than the standard one. Read more See also Buyback Mileage offset
Civil penalty: An additional amount a court can award, up to twice the actual damages, where a manufacturer wilfully failed to comply with its obligations. It is not automatic. See also Fee shifting Breach of warranty
Days out of service: The cumulative time the vehicle has been at the repair facility for warranty work. More than thirty days in total can satisfy the reasonable-attempts threshold by itself. Read more See also Reasonable number of repair attempts Recall
Fee shifting: The provision that makes the manufacturer responsible for a successful consumer's reasonable attorney fees and costs. It is why a lemon law claim can be brought without paying attorney fees out of pocket. Read more See also Lemon Law Statute of limitations
Lemon Law: In California, the consumer protection rules that apply when a manufacturer cannot repair a vehicle's covered defect after a reasonable number of attempts. The rules sit inside the Song-Beverly Consumer Warranty Act rather than in a statute of that name. Read more See also Song-Beverly Consumer Warranty Act Reasonable number of repair attempts Substantial defect
Magnuson-Moss Warranty Act: The federal warranty statute. It runs alongside California law rather than replacing it, and it can apply where a written warranty was given anywhere in the United States. Read more See also Song-Beverly Consumer Warranty Act Breach of warranty
Mileage offset: The statutory deduction for the miles driven before the first repair attempt for the defect. It is calculated by formula rather than negotiated, and it applies to a repurchase and a replacement alike. Read more See also Buyback Cash and keep
Reasonable number of repair attempts: The threshold that has to be met before a claim arises. It depends on the defect: four attempts at the same problem is a common guide, two where the defect could cause serious injury, and a vehicle out of service more than thirty cumulative days can meet it on its own. Read more See also Days out of service Substantial defect Lemon Law
Repair order: The dealer document recording a visit: the complaint, what was found, what was done and how long the vehicle was held. It is the single most important record in a claim, which is why keeping every one matters. See also Days out of service Reasonable number of repair attempts
Replacement vehicle: A substantially identical new vehicle provided instead of a refund. The same mileage offset applies, and the choice between replacement and repurchase is generally yours rather than the manufacturer’s. Read more See also Buyback Mileage offset
Song-Beverly Consumer Warranty Act: The California statute behind the state's lemon law. It applies to new and many used vehicles still covered by a manufacturer's warranty, including leased ones, and it does not ask you to show the manufacturer acted in bad faith. Read more See also Lemon Law Magnuson-Moss Warranty Act Manufacturer's warranty
Statute of limitations: The deadline for filing. In California a lemon law claim is generally brought within four years, and recent legislation has tightened the window further, so the date of the first repair attempt matters. Read more See also Fee shifting Lemon Law Days out of service
Substantial defect: A defect that affects the use, value or safety of the vehicle. A rattle or a squeak is generally not one. A brake fault that returns after repair generally is. Read more See also Reasonable number of repair attempts Breach of warranty Recall

Warranty and paperwork

Aftermarket part: A replacement part made by a company other than the vehicle manufacturer. Fitting one does not automatically void a warranty, though a manufacturer may argue it caused the fault. See also OEM part Manufacturer's warranty
Branded title: A title carrying a permanent notation such as salvage, flood or lemon. The notation follows the vehicle and affects what it can be sold for. Read more See also Lemon title Structural damage
Bumper-to-bumper warranty: The broad factory warranty covering most components for a set time or mileage. It is narrower than the name suggests and usually excludes wear items such as brake pads, wiper blades and tires. Read more See also Manufacturer's warranty Powertrain warranty
Certified pre-owned: A used vehicle sold with a manufacturer-backed warranty after an inspection. That warranty is what can bring the vehicle inside the lemon law. Read more See also Manufacturer's warranty Leased vehicle Lemon Law
Diminished value: The loss in a vehicle’s market value caused by its history, even after a proper repair. It is the basis of a cash and keep settlement. See also Cash and keep Branded title
Extended warranty: A service contract bought separately, often from a dealer or a third party rather than the manufacturer. It is not the same thing as the factory warranty, and it may not carry the same lemon law significance. Read more See also Manufacturer's warranty Certified pre-owned
Leased vehicle: A leased vehicle carries the same protection as a purchased one, because the claim rests on the manufacturer's warranty rather than the form of the transaction. Read more See also Certified pre-owned Manufacturer's warranty Buyback
Lemon title: The branding applied to a vehicle that was repurchased under lemon law and returned to the market. It has to be disclosed on resale. Read more See also Branded title Buyback
Manufacturer's warranty: The written warranty given with the vehicle. Its terms set what is covered and for how long, and lemon law rights generally depend on repairs attempted while it was in force. Read more See also Bumper-to-bumper warranty Breach of warranty Certified pre-owned
OEM part: A part made by or for the vehicle manufacturer, as opposed to an aftermarket part made by someone else. Which is used in a warranty repair can matter. See also Aftermarket part Manufacturer's warranty
Powertrain warranty: The longer warranty covering the parts that make the vehicle move: engine, transmission and drive components. It typically runs well past the bumper-to-bumper term. Read more See also Bumper-to-bumper warranty Drivetrain
Recall: A manufacturer campaign to correct a defect across a range of vehicles. A recall is not a lemon: it covers every vehicle in a build range, while a lemon claim is about your specific vehicle and its repair history. Read more See also Substantial defect Technical service bulletin Days out of service
Structural damage: Damage to the frame or unibody rather than to a bolt-on panel. It is disclosed differently from cosmetic damage and affects value. Read more See also Branded title Substantial defect
Technical service bulletin: A notice from a manufacturer to its dealers describing a known fault and the approved fix. Unlike a recall it is not announced to owners, so a TSB matching your symptom is worth knowing about. See also Recall Repair order
VIN: The seventeen-character vehicle identification number unique to your car. Recalls, warranty coverage and build records are all keyed to it. Read more See also Recall Technical service bulletin

Symptoms to document

Hard shift: A gear change that arrives with a jolt or a bang. Persistent hard shifting is a transmission complaint worth recording with dates and speeds. See also Transmission Torque converter
Limp mode: A reduced-power state a control unit enters to protect the drivetrain. It is a symptom of an underlying fault, not the fault itself. See also Loss of power ECU
Loss of power: The vehicle failing to accelerate as commanded, often with a warning light. Frequently a limp mode entered deliberately by a control unit to protect a component. See also Limp mode Turbocharger
No fault found: The outcome recorded when a dealer cannot reproduce a complaint. It still counts as a repair visit, and a run of them is itself evidence that a defect was not fixed. See also Repair order Reasonable number of repair attempts
Shudder: A vibration felt through the vehicle at a particular speed or load. Describing when it happens is what lets a technician reproduce it. See also Torque converter Brake rotor
Stalling: The engine stopping while the vehicle is in use. It is a safety defect and normally meets the stricter two-attempt threshold rather than the usual four. See also Fuel pump Reasonable number of repair attempts

Engine

Camshaft: The shaft whose lobes open and close the valves in time with the pistons. Wear or failure affects how the engine runs at every speed. See also Lifter Timing chain
Coolant: The fluid carrying heat away from the engine. Coolant appearing in the oil, or oil in the coolant, points at an internal failure rather than a leak. See also Overheating Head gasket Water pump
Cylinder: The bore in which a piston travels. Scoring or scarring of a cylinder wall lets oil past the piston, which is a common cause of excessive oil consumption. See also Engine block Oil consumption Piston ring
Engine block: The main casting that holds the cylinders. A cracked block generally means the engine is replaced rather than repaired, which is why it shows up so often in lemon law claims. See also Head gasket Cylinder Oil consumption
Engine knock: A metallic knocking or pinging from the engine. It can mean anything from ignition timing to a failing bearing, and a knock that returns after repair is a strong lemon law fact. See also Lifter Timing chain Turbocharger
Head gasket: The seal between the engine block and the cylinder head. A failed head gasket lets coolant and oil mix, which is why oil in the coolant is treated as serious rather than routine. See also Coolant Engine block Overheating
Lifter: The component that transfers camshaft motion to the valves. A collapsed or failed lifter produces a distinct tick or knock and, on some engines, has been a repeated warranty failure. See also Camshaft Engine knock
Oil consumption: Burning oil between services at a rate beyond the manufacturer’s own specification. Manufacturers often ask for a measured oil consumption test before accepting the fault. See also Piston ring Cylinder Oil consumption test
Oil consumption test: A controlled measurement in which the dealer fills the oil, asks you to drive a set distance and measures what is left. The result decides whether the manufacturer treats the consumption as a defect. See also Oil consumption Repair order
Overheating: The engine running hotter than design. Causes range from a failed water pump or thermostat to a head gasket. Continuing to drive an overheating engine usually turns a repair into a replacement. See also Coolant Head gasket Water pump
Piston ring: The rings sealing the piston against the cylinder wall. When they fail or were poorly specified, oil enters the combustion chamber and is burned, showing as blue smoke and a falling oil level. See also Oil consumption Cylinder
Timing chain: The chain keeping the crankshaft and camshaft in step. A stretched chain throws the timing out and, in the worst case, lets valves and pistons meet. See also Camshaft Engine knock
Turbocharger: A pump driven by exhaust gas that forces more air into the engine for more power. Turbo failures often announce themselves as a whistle, a loss of power or blue smoke. See also Engine knock Loss of power
Water pump: The pump circulating coolant through the engine. A failed pump causes rapid overheating and is a common warranty repair. See also Coolant Overheating

Transmission and drivetrain

Axle: The shaft carrying drive to a wheel. A broken axle is a safety failure, not an inconvenience, and can cause loss of control. See also Drivetrain Differential
Clutch: The component connecting and disconnecting engine from gearbox. Slipping, juddering or a pedal that feels wrong are the usual complaints. See also Dual-clutch transmission Transmission
CVT: A continuously variable transmission, which uses a belt and pulleys instead of fixed gears. Shuddering, droning and hesitation are the characteristic complaints. See also Transmission Torque converter
Differential: The gearset letting driven wheels turn at different speeds through a corner. Whine, clunk on take-up or leaking fluid are the signs of trouble. See also Drivetrain Axle
Drivetrain: Everything transmitting power from the engine to the wheels: transmission, driveshaft, differential and axles. Powertrain warranties are written around it. See also Powertrain warranty Differential Axle
Dual-clutch transmission: A gearbox using two clutches to pre-select gears. Smooth at speed, but low-speed shuddering and hesitation have been the subject of large warranty programmes. See also Transmission Clutch
Torque converter: The fluid coupling between engine and automatic transmission. A failing converter shows as shudder at steady speed, often mistaken for an engine misfire. See also Transmission CVT
Transfer case: On four-wheel-drive vehicles, the unit splitting drive between front and rear axles. Failure can leave the vehicle stuck in one mode. See also Drivetrain Differential
Transmission: The gearbox matching engine speed to road speed. Slipping, harsh shifts, hesitation and refusal to engage a gear are the symptoms that most often turn into claims. Read more See also Torque converter CVT Dual-clutch transmission

Electrical and electronics

ADAS: Advanced driver assistance systems: lane keeping, automatic braking, adaptive cruise, blind spot monitoring. False activations are a safety complaint, not a nuisance one. See also Sensor CAN bus
Alternator: The generator that charges the battery while the engine runs. A failing alternator flattens the battery and produces warnings across unrelated systems. See also Battery Parasitic draw
Battery: The twelve volt battery that starts the engine and runs the electronics, separate from the traction battery in an electric vehicle. A battery that keeps going flat usually points at a charging fault or a parasitic draw rather than the battery itself. See also Alternator Parasitic draw High-voltage battery
CAN bus: The network the vehicle’s computers use to talk to each other. A fault on the bus produces warnings across several systems at once, which is why unrelated lights often appear together. See also Infotainment system ECU
Check engine light: The malfunction indicator lamp. It means a control unit has stored a fault code; it does not say how serious the fault is. A light that returns after repair is a documented repeat. See also Diagnostic trouble code Sensor
Diagnostic trouble code: The code stored when a control unit detects a fault, read at the dealer with a scan tool. Codes appear on repair orders and are useful evidence of a recurring problem. See also Check engine light Repair order
ECU: An electronic control unit: one of the many computers running the engine, transmission, brakes and body systems. Replacing one is often the last step after software updates fail. See also CAN bus Software update
Infotainment system: The central screen and its software: navigation, audio, phone connection. Blank screens, reboots and lost connectivity are among the most reported defects on modern vehicles. See also CAN bus Software update
Parasitic draw: Current drawn while the vehicle is switched off, flattening the battery overnight. Tracing one is slow work, which is why these faults so often take several visits. See also Battery Alternator
Sensor: A device reporting a condition to a control unit. Many warning lights trace to a failed sensor rather than the system it monitors, which is why diagnosis matters. See also ECU ADAS Check engine light
Software update: A reflash of a control unit’s programming. Dealers frequently apply one as a first repair attempt, and an update that does not resolve the complaint still counts as a repair attempt. See also ECU Repair order

Brakes, steering and suspension

ABS: The anti-lock braking system, which prevents the wheels locking under heavy braking. An ABS warning is a safety fault and is treated differently from a comfort complaint. See also Brake caliper ADAS
Brake caliper: The clamp that presses the pads against the disc. A seized caliper causes pulling, uneven pad wear and overheating at one wheel. See also Brake rotor ABS
Brake fade: Loss of braking effectiveness as components overheat. Fade that appears in ordinary driving is a defect, not a characteristic. See also Brake rotor Brake caliper
Brake rotor: The disc the pads grip. Warping produces a pulsing pedal and a shudder felt through the steering under braking. See also Brake caliper Brake fade
Control arm: The link locating a wheel to the body. Worn bushings produce clunks over bumps and can affect alignment. See also Strut Wheel alignment
Death wobble: A violent oscillation of the steering at speed, most associated with solid front axle vehicles. It is a safety complaint and should be documented precisely when it occurs. See also Steering rack Strut
Electric power steering: Steering assisted by an electric motor rather than a hydraulic pump. Failures show as sudden heaviness, a warning light, or the assistance cutting in and out. See also Steering rack ECU
Steering rack: The mechanism converting steering wheel rotation into wheel movement. Play, knocking and leaks are the usual complaints. See also Electric power steering Wheel alignment
Strut: A combined shock absorber and suspension mount. Knocking over bumps and uneven tire wear are the common signs. See also Control arm Wheel alignment
Wheel alignment: The angles at which the wheels sit relative to the road and each other. Persistent pulling that returns after alignment often points at something structural rather than the settings. See also Structural damage Steering rack

Fuel, exhaust and emissions

Catalytic converter: The emissions device converting harmful exhaust gases. Failures are expensive and are often covered for longer than the bumper-to-bumper term under emissions warranty rules. Read more See also Powertrain warranty Check engine light
Diesel particulate filter: The filter trapping soot in a diesel exhaust. Repeated regeneration failures leave the vehicle in a reduced-power state. See also Catalytic converter Loss of power
EGR valve: The exhaust gas recirculation valve, which routes some exhaust back into the intake to lower emissions. Sticking causes rough running and a check engine light. See also Catalytic converter Check engine light
Fuel injector: The valve metering fuel into the engine. A leaking or blocked injector causes misfires, rough running and poor economy. See also Fuel pump Misfire
Fuel pump: The pump delivering fuel to the engine. Failure typically causes stalling, hard starting or the vehicle stopping while being driven. See also Fuel injector Stalling
Misfire: A cylinder failing to burn its charge properly. Felt as shaking, hesitation or a flashing check engine light, which indicates damage to the catalytic converter is possible. See also Fuel injector Check engine light Catalytic converter

Climate, body and interior

Cabin water leak: Water entering the interior, usually through a seal, a sunroof drain or a windscreen bond. Damp carpets lead to mould and electrical faults, so it is rarely only a comfort issue. See also HVAC Mould
Compressor: The pump driving the air conditioning circuit. Failure means no cooling, often with a noise or a blown fuse. See also HVAC
HVAC: Heating, ventilation and air conditioning. Blowing hot when set to cold, or failing on one side only, are common defects. See also Compressor Cabin water leak
Mould: Growth arising from persistent damp inside the cabin. It is a health concern as well as a defect, and it is evidence that a water leak was not resolved. See also Cabin water leak
Panel gap: The spacing between body panels. Uneven gaps can indicate poor assembly or previous repair. See also Structural damage

Electric and hybrid

Battery degradation: The gradual loss of usable capacity over time. Some loss is normal; loss beyond the warranty threshold, or a sudden drop, is not. See also High-voltage battery State of charge
Charging port: The socket and its latch. Failures leave a vehicle unable to accept a charge or unable to release the cable. See also Onboard charger High-voltage battery
High-voltage battery: The traction battery propelling an electric or hybrid vehicle. It carries its own longer warranty, and degradation beyond the manufacturer’s stated threshold can be a defect. See also State of charge Battery degradation Thermal management
Onboard charger: The unit converting AC supply into DC for the battery. A failure means the vehicle will not charge from a normal outlet or wallbox. See also High-voltage battery Charging port
Range anxiety: The gap between rated range and what the vehicle actually achieves. Where the shortfall is large and repeatable, it is a defect rather than driving style. See also State of charge Battery degradation
Regenerative braking: Braking that recovers energy back into the battery. Inconsistent or unexpected regeneration is a driveability complaint worth documenting. See also High-voltage battery ABS
State of charge: How full the traction battery is, shown as a percentage. A vehicle that will not charge to its rated range is reporting a defect, not a preference. See also High-voltage battery Battery degradation
Thermal management: The system keeping the traction battery within its temperature range. Failures show as reduced charging speed, reduced power or warnings in hot weather. See also High-voltage battery