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🚗 WHAT TO CHECK BEFORE BUYING A USED CAR – COMPLETE GUIDE 2026

Updated October 2025 — by Gianni Tritella. Buying a used car can be a great way to save money, but only if you know what to really check . With my experience in the spare parts and diagnostics sector, I've compiled in this guide all the essential steps every driver should follow before signing the contract.

From checking the engine and mechanical components to analyzing documents and maintenance history , through the new OBD electronic diagnostics and visual inspections of the bodywork, here you'll find a practical method to avoid unpleasant surprises and choose a reliable used car. If you're about to buy, read this guide carefully: it will save you time, stress, and hundreds of euros.

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✅ Introduction

Buying a used car in 2026 may seem like a bargain, but behind a reasonable price often lie technical or administrative issues that can turn a good purchase into an unexpected expense. Modern cars, packed with electronics, sensors, and control units, require much more thorough inspections than in the past.

From my experience as a spare parts dealer and garage consultant , I can confirm that over 70% of the used cars analyzed have undeclared defects: small leaks, errors stored in the control unit, or missed maintenance that only emerge after purchase.

In this guide, I'll show you a practical and concrete method for comprehensively evaluating a used car: from mechanical inspections to document verification and electronic diagnostics. Following this checklist means purchasing with awareness and minimizing the risk of finding yourself with a problematic vehicle a few months later.

Whether you're a first-time driver or an enthusiast with years of driving under your belt, this guide will help you quickly recognize reliable cars and avoid those that hide expensive surprises.

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🔧 Basic mechanical checks

The heart of a car is its mechanical parts: the engine, transmission, and brakes are what truly determine the vehicle's reliability and safety. Even a seemingly "nice" car can hide costly problems if not carefully inspected.

Before you buy, take the time to do a thorough check — ideally with a trusted mechanic — following these key points:

• Engine and leaks: Open the hood and carefully inspect gaskets, covers, and seals. Traces of oil or deposits may indicate leaks. Blue exhaust smoke suggests oil consumption, while persistent white smoke may indicate a damaged head gasket.
• Gearbox and clutch: During the road test, perform gear changes both cold and hot. The shifts should be precise, without grinding or metallic noises. If the clutch slips on a hill or the pedal travels irregularly, you need to adjust the gears.
• Suspension and ride: Check that the car doesn't dip to one side or creak. Worn shock absorbers and silent blocks compromise comfort and road holding. Also check for abnormal tire wear.
• Brakes: There should be no vibration or metallic noise when braking. Good-condition discs and pads ensure proper stopping distances and safety. Also check the brake fluid level.
• Steering and linkages: Check for any play, vibrations, or noises while driving. A steering wheel that doesn't return easily or vibrates indicates problems with the suspension or steering gear.
• Timing belt: This is one of the most critical components. If there's no documentary proof of replacement, consider it an expense to be addressed immediately: a breakage can seriously damage the engine.

A thorough check of these points, carried out before signing the contract, can save you thousands of euros in repairs and guarantee you a truly reliable car for years to come.

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🧾 Documents and legal checks

A car may seem perfect at first glance, but if the paperwork isn't in order, you risk finding yourself with a vehicle that isn't registered, subject to administrative seizure, or facing legal problems . Before finalizing the purchase, carefully check every detail of the documents: it's the most important step to protect yourself.

Here are the checks you should never skip:

• Chassis number: Make sure it exactly matches the one engraved on the vehicle. It must be legible and free of any signs of tampering. If you notice any abrasions or inconsistent numbers, stop the deal immediately.
• Digital Certificate of Ownership (CDPD): This now replaces the old paper document. You can request an updated copy from the PRA (Regional Road Traffic Authority) to verify that the seller is the owner and that there are no mortgages, leases, or active liens.
• Vehicle registration document: must contain all correct information (chassis, license plate, engine size, fuel type, homologation). Verify that there are no "exported vehicle" or "deregistered" notes.
• Periodic inspection: check deadlines, mileage, and results on the Motorist Portal . Decreased mileage between inspections is a sign of odometer tampering .
• Service history: Request invoices or service booklet stamps. If the seller says "all services have been performed" but provides no proof, consider the vehicle uncertified.
• Administrative seizures and foreclosures: with a PRA search, you can verify that your vehicle is not subject to any seizures. If any, it cannot be transferred until they are removed.
• Legal guarantee of conformity: If you purchase from a dealer or reseller, you are entitled to a 12-month mandatory warranty for undeclared defects (Legislative Decree 206/2005). Make sure this is specified in writing in the contract.

Checking your documentation is the first real step towards a safe purchase. A complete PRA (Italian Vehicle Registration Authority) certificate costs just a few euros , but it can save you from scams and lengthy, costly paperwork. Never trust anyone who tells you "everything is in order" without providing concrete proof.

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💡 Electronic diagnostics and recommended tools

Modern cars are veritable computers on wheels. Control units, sensors, and electronic modules manage everything: from starting the engine to operating the brakes and even the climate control. For this reason, before buying a used car in 2026, a complete electronic diagnostic is essential .

Even if you're not a technician, you can perform a basic check with a Bluetooth OBDII scanner . It connects to the diagnostic port (usually under the dashboard) and, via a smartphone app, allows you to:

• Read any engine, ABS, airbag and automatic transmission faults .
• Monitor real-time parameters such as temperatures, engine rpm, battery voltage and turbo boost.
• Check to see if any errors have been cleared recently — a typical sign of someone trying to “mask” problems.
• Analyze FAP/DPF maintenance and regeneration data (in newer diesel cars).
• Check the mileage stored in the ECUs of some cars, useful for unmasking odometer manipulation.

When diagnosing, it's important to go beyond the engine control unit: the most costly faults often lie in secondary modules (ABS, transmission, airbags, body computer). A complete scan provides a realistic picture of the car's condition.

For those who want a more thorough check, you can ask the seller to allow a workshop diagnosis . The average cost (€40–€60) is a small investment compared to the risk of buying a car with faulty control units or serious, undeclared faults.

Finally, remember to check the 12V battery as well: low voltage or abnormal charge values ​​can indicate weak alternators or electrical problems affecting the entire system. A thorough diagnosis, even in just a few minutes, can reveal what you can't see with the naked eye.

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🛡 How to recognize a crashed or rigged car

A shiny, well-washed body can be deceiving, but recognizing a damaged or tampered car is possible even without professional tools. All it takes is a keen eye and a few targeted checks to avoid poorly repaired vehicles or vehicles with falsified mileage.

Here are the elements you should never overlook during the inspection:

• Uneven paintwork: Look at the car in natural light. Differences in shade between the hood, bumper, and doors may indicate repainting. If the color "flips" between adjacent panels, the car has likely been involved in an accident.
• Paint thickness: With a simple digital thickness gauge (less than €50), you can measure the paint layer. A value greater than 200 microns indicates painting or filling, indicating major repairs.
• Fresh bolts or welds: Open the hood and trunk and inspect the bolts securing the fenders and crossmembers. If they show signs of disassembly or scratched paint, the car has undergone structural work. The same applies to "new" or non-original welds in the engine compartment or floor.
• Body alignment: Check that the doors, hood, and tailgate close with equal resistance and that the gaps between the panels are even. Unevenness or difficult closing are signs of a warped or poorly repaired frame.
• Worn interior and steering wheel: A car with less than 80,000 km should have seats, steering wheel, and gear knob in good condition. If you notice excessive wear or discolored plastic, the mileage claim is likely manipulated .
• Seat belts and airbags: Check the manufacturing date on the seat belt labels (often near the anchor). If it's replaced or missing, it may have been repaired after an accident.
• Windshield and headlights: Check for cracks, dents, or differences in brand between the headlights—these often indicate a head-on collision.

A careful inspection of these details, perhaps with the aid of a flashlight and a pocket mirror, can reveal defects that sellers try to hide. If you notice more than one suspicious sign, always ask for an inspector to inspect the car or avoid the purchase: it's better to miss an opportunity than to buy a problem.

Remember: in 2026, the most common scam remains deducting mileage . To protect yourself, compare the declared value with the official inspection data on the Motorist Portal or with the logs stored in the control units via OBD diagnostics.

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💰 Practical advice on pricing and negotiation

Setting the right price for a used car is often the most delicate part of the purchase. A price that's too low can hide serious flaws, while one that's too high isn't always synonymous with quality. The key is knowing the model's true value and negotiating intelligently, with the data in hand.

• Always compare market prices: consult portals like AutoScout24 , Subito , and Quattroruote to check average prices for the model, year, and trim. Compare at least 10 similar listings to get an idea of ​​the real price.
• Be wary of excessively low prices: a vehicle offered at more than 20% below the average almost always indicates mechanical problems, low mileage, or incomplete documentation. If the seller insists on a "bargain price," always ask to have it checked out by a trusted garage.
• Ask for a test drive: this is when any noises, vibrations, or hidden defects emerge. Test drive with the engine warm and ask to drive both in the city and on country roads. If the seller refuses, consider the deal closed.
• Consider the cost of future maintenance: a cheap car can be expensive to maintain (belt, clutch, tires, filters). Check the availability and prices of spare parts—also in our shop—to avoid surprises after the purchase.
• Check the warranty: if you buy from a dealer or retailer, the law (Legislative Decree 206/2005) provides a mandatory 12-month warranty for undeclared defects. Always ask for this to be specified in the contract and check for any restrictive clauses.
• Don't let rushing get you down: those who push you to "decide now" are afraid you might find something wrong. Take your time to evaluate and, if necessary, request a pre-purchase inspection or appraisal.
• Negotiate transparently: show the seller your reference quotes and offer a reasonable price based on the defects found. Fair negotiations are mutually beneficial.

Remember: in the used car market , the right price is one that reflects the vehicle's true condition . Be wary of "super deals" and prioritize transparency: a well-maintained car with a documented history is always worth more than a low price with no guarantees.

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🔍 Final Checklist 2026

Section	Check	Outcome
Motor	Oil leaks, smoke, abnormal noises	☐
Change	Regular grafts, no tearing	☐
Brakes	Good discs and pads	☐
Electronics	No active OBD errors	☐
Documents	Inspection and coupons ok	☐
Body	No apparent incidents	☐

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❓ Frequently Asked Questions

Do you need to bring a trusted mechanic?

Yes, always recommended: it can detect hidden defects that escape a visual inspection.

Is it better to buy from a private individual or a dealer?

You'll save money by going private, but you won't get a guarantee. You'll pay more at a dealership, but you'll get 12 months of legal protection.

Can I check online if a car is stolen or seized?

Yes, through the Motorist Portal or by requesting an updated PRA certificate.

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📌 Conclusions

Buying a used car in 2026 requires attention, tools, and method. Following this guide will help you avoid costly mistakes and make informed choices.

The golden rule? If you're not happy with something, don't buy it. A check today can save you thousands of euros in expenses later.