MacBook Beeps & Apple Diagnostics Codes
Updated
Intel Macs beep during start for memory or firmware problems. Apple silicon Macs do not beep. Every Mac can run Apple Diagnostics, which ends with a reference code such as PPP001.
How it works
Count the blinks or beeps, then open the matching table below.
Not sure? The finder above takes the code and gives the meaning.
Covers: MacBook, MacBook Air, MacBook Pro (Intel and Apple silicon).
Startup beeps (Intel Macs)
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The beeps sound at the very start, while the screen is still black. They are not the normal startup chime.
| Code | What it means | What to check |
|---|---|---|
1 beep every 5 s | No memory (RAM) detected | Reseat / replace the RAM; soldered RAM = board repair (memory rails, RAM chips). |
3 beeps, 5 s pause, repeating | The memory failed its integrity check | Check or replace the RAM. |
3 long, 3 short, 3 long | Firmware is being restored | Wait - the Mac should start normally after a progress bar. |
Apple Diagnostics reference codes
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Apple silicon: hold power until Options, then Command-D. Intel: hold D at start (or Option-D). The code appears at the end of the test.
| Code | What it means | What to check |
|---|---|---|
ADP000 | No issues found | - |
ALS001 | Ambient light sensor may be faulty | Sensor / display assembly. |
BMT001 | Touch ID sensor may be faulty | Touch ID (power button) and its cable. |
CNW001 | Wi-Fi hardware may be faulty (also CNW003-006, 009) | Wi-Fi module / antennas. |
CNW007 | No Wi-Fi networks found (CNW007-008) | Test near a Wi-Fi network; else Wi-Fi hardware. |
DFR001 | Touch Bar may be faulty | Touch Bar and its cable. |
IMU001 | Accelerometer / gyroscope may be faulty | Board sensor. |
LAS001 | Lid sensor may be faulty (LAS001-004) | Lid angle / hall sensor and its cable. |
NDC001 | Camera may be faulty (also NDC003-006) | Camera and display cable. |
NDD001 | USB hardware may be faulty | Unplug all USB devices and retest. |
NDK001 | Keyboard may be faulty (also NDK003-004) | Keyboard / top case. |
NDL001 | Bluetooth hardware may be faulty (NDL001-002) | Wireless module / antennas. |
NDR001 | Trackpad may be faulty (also NDR003-006, 008) | Trackpad and its cable. |
NDT001 | Thunderbolt hardware may be faulty (NDT001-006) | Unplug Thunderbolt devices; USB-C ports / board. |
NNN001 | Serial number not detected | Board identity - needs service. |
PFM001 | System Management Controller (SMC) may be faulty (PFM001-007) | Board-level (SMC). |
PFR001 | Firmware may be faulty | Firmware restore (DFU) / service. |
PPF001 | Fan may be faulty (also PPF003-004) | Clean / replace the fan, check its cable. |
PPM001 | Memory module may be faulty (PPM002-016 = onboard memory) | RAM - onboard memory = board repair. |
PPN001 | Power management may be faulty (PPN001-002) | Board power management. |
PPP001 | Power adapter may be faulty (PPP001-008, PPP020 = none found) | Check the adapter and cable; try another original adapter. |
PPP017 | Both ports of a 35 W dual USB-C adapter in use | Use one port while testing. |
PPP018 | Adapter does not support fast charging | Use a fast-charge adapter / cable. |
PPR001 | Processor may be faulty | Board-level. |
PPT001 | Battery not detected | Battery connector / battery. |
PPT002 | Battery needs replacing soon (PPT002-003) | Plan a battery replacement. |
PPT004 | Battery needs service | Check the battery; safe to use until checked. |
PPT005 | Battery not installed properly | Stop using the Mac until it is checked. |
PPT006 | Battery needs service, not working normally | Battery service. |
PPT007 | Battery holds much less charge - replace | Replace the battery. |
PPT021 | Battery too low to run the test | Charge to at least 6 % and retest. |
VDC001 | SD card reader may be faulty (also VDC003-007) | Card reader. |
VDH001 | Storage may be faulty (VDH001-004) | SSD / storage - back up first. |
VDH005 | Cannot start macOS Recovery | Storage / firmware - service. |
VFD001 | Display or graphics processor may be faulty (VFD001-007) | Display, display cable or GPU. |
VFD008 | HDMI controller may be faulty (VFD008-009) | HDMI port / controller. |
VFF001 | Audio hardware may be faulty (VFF001-003) | Speakers / audio board. |
No light, no beep, no code at all?
- Look at the charger's own light. Off = charger, cable or outlet. If it blinks or goes out the moment you plug it into the laptop, there is a short circuit inside the laptop - unplug it.
- Power reset (EC reset): charger out (and the battery if it comes out), hold the power button 30 seconds, then plug in and try again. Laptops with a built-in battery often have a small reset hole underneath.
- Charge it for 30 minutes with the original charger: a deeply empty battery - or a new laptop in shipping mode - will not start at once.
- Remove what was added last (RAM, SSD, cards) and reseat the RAM.
- Connect an external monitor: a picture there means the laptop's screen, cable or backlight - not the board.
- Still dead: it is a board-level fault - charger chip, a shorted power rail, or the BIOS chip. A repair technician measures the rails in their power-on order.
Step-by-step: the no-power troubleshooter
No beeps on this page for your laptop? Many laptops beep with their BIOS maker's codes - see the BIOS beep codes (AMI, Phoenix, Insyde).
Different code, or still not starting after these checks? Post the code and the laptop model on the NoPowerFix repair forum - board-level technicians answer, and every confirmed fix improves these tables.
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