What is the diagnostic mode on an iPod

AppleWiki

Various parameters of the iPod can be checked in the iPod Diagnostic Mode. The Diagnostic Mode can be accessed by pressing the following buttons simultaneously while the Apple logo has been reset:

  • 1-3. Generation: Back, Forward and Select buttons (center)
  • 4th generation and newer: back and select button

The tests can be selected with the back and forward buttons. A test is activated with the selection key and usually ended with the play key. Another reset exits the diagnostic mode.

1G to 4G

The following tests are offered in the 1G to 4G devices, depending on the model:

5 IN 1Runs the following tests in sequence: LCM, SDRAM, RTC, FLASH, FIREWIRE
RESETTest whether a reset can be carried out
KEYTest of all buttons
AUDIOAudio test
REMOTETest the iPod remote control on the headphone cable
FIREWIREFireWire test
SLEEPSleep mode. Is terminated by a reset.
A2DPower supply test. Gives different results depending on whether battery operation, connected to an external power supply or computer
OTPO CNTScroll wheel test
LCMDisplay test. Various test patterns are displayed with the selection key.
RTCTest of the internal clock (Real Time Clock).
SDRAMMemory test
FLASHTests the flash memory with the firmware and returns the firmware version.
OTPO or Wheel A2DTests the analog-to-digital converter of the scroll wheel. The test can only be ended with a reset.
HDD SCANChecks the hard drive for errors. Depending on the memory size, the test may take a while.
RUN INTests the iPod chipset

5G - iPod photo / iPod video

The following tests are offered in the devices with color display, depending on the model:

MemoryTests SDRAM, IRAM and FLASH
IOTests Comms (FireWire, USB and remote control), Wheel (ClickWheel and buttons), LCD (display), HeadphoneDetect, HardDrive with HDSpecs (HD characteristics), HDScan (scanning the HD), HDSMARTData (SMART data), HDRW (write / Reading test), audio with playback and MIC (microphones)
powerPhillipsID (test power supply) and A2D (analog / digital converter test)
statusSharp (Dispay), HP (headphones connected?), FWPWR (power supply via FireWire?), USBPWR (power supply via USB?)
SysCfgVarious system data
Disk mode 
Reset 
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