People call us about two different jobs that sound alike. One is "I am about to buy this car. Is it any good?" The other is "My car is doing something wrong. What is it?" The first is an inspection. The second is a diagnosis. They take different time, different tools and often a different kind of shop, so it pays to know which one you need before you book anything.
The short answer
- You are buying a car you do not own yet: you want a pre-purchase inspection. It looks at the whole car and tells you what condition it is in.
- You own the car and it has one specific problem: you want a diagnosis. A repair shop tracks that one fault down to its cause.
Stephon, who owns Car Pro Inspections, puts it in one line: "Diagnostics is different than an inspection."
What an inspection is
A pre-purchase inspection is wide. One of our certified technicians works through the whole car: mechanical and safety systems, the underbody and structure, brakes, suspension and steering, a dealer-level diagnostic scan, paint and body, the interior, and a road test when the seller allows it and it is safe and legal to drive. You get a written report with photos.
In Stephon's words: "The scope of a pre-purchase inspection is to check many items and not to focus in and diagnose one specific item."
Our inspection is non-invasive, so we do not take anything apart as standard. If you want an underbody panel removed, ask us when you book. Plan to have the car available for 1 to 2 hours, depending on the vehicle and the package.
What a diagnosis is
A diagnosis is narrow. It starts with one problem you already know about, a noise, a warning light, a leak, and works until it finds the cause. Stephon describes it as a specific problem being troubleshot, which can mean taking parts off, special equipment, or a technician with different training for that system. He says one issue alone can take about an hour.
That work belongs at a repair shop, where the car can stay on a lift, parts can come off, and the people who find the cause can also quote the repair.
"Don't you scan the car? Isn't that a diagnosis?"
Every package includes a dealer-level diagnostic scan. Depth varies by make and year, some EVs restrict access, and cars from 1995 and earlier, including most classics, may not scan at all, so we check those mechanically.
The scan is one part of the inspection, not a diagnosis of each code. Here is what you get from it:
- Essential: a plain-English summary naming the affected systems and next steps.
- Enhanced and Elite: that summary plus each code explained.
If you want to know what a scan can and cannot tell you about a car someone is selling, read why a check engine light can be cleared before a sale.
What we do when we find a problem
When the technician finds something whose cause is not clear on the spot, the report says what the car does, then recommends having it diagnosed. For example: "Squealing noise from the front of the engine at idle. We recommend having it diagnosed." If the technician has an idea what it is, the report may add it as a possibility, never as a fact.
Why not stop and diagnose it there? Because the seller has given us the car for a set time, and an hour spent chasing one fault is an hour not spent on the rest of the car. You are paying for the whole picture. One problem you already know about is something you can price in, ask about, or have diagnosed. The ones nobody has found yet are what an inspection is for.
A call we took last week
A past customer called us. His own car had a problem, and he was deciding whether to repair it or replace it. We told him he did not need an inspection for that: he needed a repair shop to diagnose the problem and tell him what the fix would cost. He said he would call us when he shops for the next car.
That is the honest answer, and it is the one we give.
The car you want to buy already has a known issue
Say the seller mentions a noise, or you spot a damp patch under the engine. You still want the inspection, because you need the rest of the car checked too. And you can point us at that one thing.
On Enhanced (up to 3) and Elite (up to 6), you name your Areas of Concern when you book. Your inspector gives each one a closer look than the standard checklist does and answers each one in writing in your report: where they looked, what they found, and anything that could not be seen without taking parts off. It is still a non-invasive inspection. On Essential, your inspector still reads what you list, but each one does not get its own closer look and written answer.
If the report then recommends having something diagnosed, you decide what to do with that before you pay for the car: ask the seller to have it diagnosed, ask for a price that reflects it, or keep looking.
Frequently asked questions
Do you diagnose check engine lights? We scan the car and tell you what the scan shows. Finding the exact cause of a code is a diagnosis, and when the report needs one, it says so.
Can you take parts off to look closer? Our inspection is non-invasive, so we do not take anything apart as standard. If you want an underbody panel removed, ask us when you book. Where something could not be seen without taking parts off, the report tells you.
I own my car and it has a problem. Should I book an inspection? For one specific problem, no. A repair shop's diagnosis is the right tool, and we will tell you that if you call.
What does a pre-purchase inspection include? It depends on the package. Every package covers mechanical and safety systems, the underbody and structure, brakes, suspension and steering, a dealer-level diagnostic scan and a road test when it is allowed and safe. The full list for each package is on the services page.
Buying a used car in the Atlanta or Orlando area? Call us at 833-644-0800 and talk it through before you buy. Then book your inspection at carproinspections.com.