Apple's own verdict · 3 minutes

Make the Mac test itself

Every Apple Silicon MacBook carries a hardware self-test in its firmware. It runs before macOS loads, so nothing a seller has installed can influence it, and it needs no internet connection. It is the closest thing to a second opinion you can get in a car park.

Step one

Boot it into diagnostics

Shut it down completelyNot sleep — Apple menu → Shut Down. Unplug every accessory except the charger.

Hold the power buttonKeep holding past the Apple logo until “Loading startup options” appears. On Touch ID models this is the Touch ID key.

Press ⌘DThe test runs itself and takes about two minutes. Let it finish — a partial run reports nothing.

Step two

Look up what it reported

ADP000CleanEverything — No issue found. This is the result you want, and the only clean one.

PPT004RepairableBattery — Battery needs replacing. A known price, not a deal-breaker — deduct it.

PPT006RepairableBattery — Battery will not hold charge properly. Same repair, same deduction.

PPN001RepairableCharger — The adapter attached is wrong or failing. Test again with a known-good one before believing it.

VDC003RepairableCamera — Camera sensor fault. Cheap to live with, awkward to repair — it is part of the display assembly.

NDL001RepairableBluetooth — Bluetooth radio fault. On Apple Silicon the radio is on the logic board.

NDI001Board-levelWi-Fi — Wi-Fi module fault. Soldered to the logic board — this is a board-level repair.

VDC001Board-levelDisplay / GPU — Display subsystem fault. The most expensive single part of the machine.

PFM006Board-levelPower controller — SMC fault. Unpredictable charging and sleep behaviour. Walk away.

PFR006Board-levelPower delivery — Onboard power delivery fault. Logic board repair, often close to the value of the Mac.

ADP000 does not mean the Mac is fine

Apple Diagnostics checks that components respond, not that they work well. It passes machines with dead pixels, blown speaker drivers, worn trackpad clicks and thermal throttling — every fault a buyer actually notices. Treat a clean result as a floor, not a verdict, and do the rest yourself.

Apple checked that it responds. Now check that it works.

Run the full inspection

Worth buying alongside it

The bits and pieces most second-hand Macs turn up without

Back Market — Refurbished MacBooksA marketplace for second-hand Macs that have been through a refurbisher, if the one in front of you turns out to be a dud.View ›Refurbed — Refurbished MacBooksMuch the same idea, mostly European stock. Worth comparing against the others before you commit.View ›eBay Refurbished MacBookseBay’s refurbished section, where the seller is a dealer rather than someone you meet in a car park.View ›

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