Apple Hardware Test (AHT) and Apple Diagnostics (AD) Codes
Apple Diagnostics(AD) replaces built-in Apple Hardware Test(AHT) for devices manufactured after 2013. Some older devices will also load AD instead of AHT if you update the OS or use Option+D to download it online. Many older devices lose AHT after upgrading your OS, since it wipes it from the hard drive and its not available online.
AHT Codes are more complex and give more information on the issue.
The first part is a device name:
- 4ETH: Ethernet controller
- 4IRP: Main Logic board
- 4MLB: Logic board controller
- 4PRC: Processor
- 4HDD: Hard disk
- 4MHD: External disk
- 4YDC: Video card
- 4SNS: System sensor
- 4MOT: Fan motor
- 4MEM: Memory module
- 4AIR: AirPort wireless card
Most of them pretty straight-forward except 4SNS which will be follower by either V (Voltage or Current sensor) or T for thermal sensor.
- A: Ambient Air Sensor
- B: Battery
- C: Central Processors (CPU)
- D: DC (Direct Current)
- e: PCI-Express Slot
- F: FireWire Port
- G: Graphics Processor (GPU)
- H: Hard Disk
- h: Heat Sink (or Heat Pipe)
- L: LCD display
- M: Memory (or Memory Riser Boards)
- m: Miscellaneous (Peripherals such as a Battery Charger)
- N: North Bridge (Logic Board Controller)
- O: Optical Drives
- P: Power Bus
- p: Power Supply
- s: Trackpad
- W: Airport Wi-Fi Card
For example: 4SNS/1/40000000: TA00 means Ambient thermal sensor.
If your device is newer than 2013 or you booting it online from some older devices, there's AD which is much less reliable and kind of helps you to book an appointment in Genius Bar instead of showing the real issue. Use Apple MRI to gather more information.
|Code||Explanation||Actual Board problem|
|ADP000||No issues found|
|CNW001…06||Wifi not detected|
|NDC001…6||Camera not detected|
|NDR001||Trackpad not detected|
|NNN001||A serial number was not detected.||Don't forget to correct SN/CRC/CleanME|
|PFM001||There may be an issue with the System Management Controller (SMC).
Often means thermal or current sensor failure.
Most common problem after water damage.
|PFM006||Trackpad on 820-00165
Battery on 820-01958
|PFR001||There may be an issue with the computer's firmware.|
|PPF001||There may be an issue with the fan.|
|PPM001||There may be an issue with a memory module.|
|PPM002||There may be an issue with the onboard memory.|
|PPP001||There may be an issue with the power adapter.|
|PPR001||There may be an issue with the processor.|
|PPT001||The battery was not detected.|
|PPT002||The battery will need to be replaced soon. It is functioning normally, but holds less charge than it did when it was new.|
|PPT004||The battery requires service. The battery is not functioning normally, though you may not notice a change in its behavior or the amount of charge it holds. You can continue to use your battery before it’s checked without harming your computer.|
|PPT005||The battery is not installed properly. Shut down and discontinue use. The computer requires service.||Check battery communication cable on 2015 and later models.|
|PPT006||The battery requires service. The battery is not functioning normally, though you may not notice a change in its behavior or the amount of charge it holds. You can continue to use your battery before it’s checked without harming your computer.|
|PPT007||The battery needs to be replaced. The battery is functioning normally but holds significantly less charge than it did when it was new. You can continue to use the battery until you replace it, without harming your computer.|
|VDC001||There may be an issue with the SD card reader.|
|VDH002||There may be an issue with a storage device.|
|VDH005||Unable to start OS X Recovery.|
|VFD001||There may be an issue with the display.|
|VFD006||There may be an issue with the graphics processor.|
|VFF001||There may be an issue with the audio hardware.|