Secret Startup Commands for Garmin handhelds
There are several undocumented commands available,
primarily at startup, on Garmin handheld receivers. This article will
attempt to document some of the features available. I will try to
document these in a universal way although details may differ
depending on the unit you have. There are variations among models and
among software releases within models. There is no attempt to provide
100% mapping to a particular model or release. Instead I have used a
"try it" approach. I have documented what you may see and you will
need to verify exactly what you did see. You may wish to print this
out and check mark the features that are applicable to your unit.
Note that many of these features are not documented by Garmin for a
reason. They are generally for testing the device and are not intended
for end users. The modes are not supported by Garmin and may cause you
to lose data in your machines. Try this at your own risk!
One major feature that is revealed when using these undocumented
test modes is that there is a thermometer inside your Garmin unit. The
intent of this thermometer is to compensate the internal time-of-day
clock for changes in temperature which will cause the internal crystal
to drift. To a lesser extent it is also used to adjust the contrast of
the display screen for temperature changes. It will not measure
ambient temperature except when the unit is first turned on since the
internal temperature is changed due to the heating effects of the
electronics in the unit. The thermometer based correction works by
building a table of correction values that are then applied to the
internal clock. This is only used to obtain an initial fix since after
the fix the satellite data is used to keep the clock accurate.
Similarly while you have a fix the accurate clock can be
used to update the temperature data in the table which means the unit
will compensate for aging parts and even the complete loss of the
table.
Special key startup sequences
The three keyboard keys on the right side of the unit have special
significance if held down while powering on the unit. These keys are
generally called page, mark, and enter. On the GIII units and some
other units the center key is call menu but for our purposes it
behaves the same. On Street Pilots the equivalent keyboard names will
have to be used. These are page, option, and enter. See below for
etrex and emap startup sequences. Other Garmin units typically have
some of these special modes as well although the key sequences may be
slightly different. I have documented some of them below.
- Page - Holding the page key down while powering up the unit will
cause an immediate forced cold start (Auto Locate). On the street
pilot this is the only way to observe the software revision level. On
the G-III this is reported to lose the temperature compensation
data.
- Mark - Holding the mark key down while powering up will totally
reset unit. You will lose all user supplied data and preferences. The
machine will be set back to factory defaults. Be careful, there is
no warning message. All data will be lost! To continue after
a reset click here.
On some units this feature has been documented in the manual and
will offer a warning message before erasing. However, some versions of
software, even on these machines, do not offer the warning. Do not
depend on the documentation here. Have everything of value backed up
before trying this. The big plus of this feature is that this reset
can fix problems with the unit that will avoid having to send it back
to Garmin.
Note that setting back to factory defaults means everything. You
will not only lose things that you can backup but also settings that
you cannot. For example the user defined datum, the user defined grid,
any preferences and datums that you have set up, any customization of
any kind. The leap second data will be gone. The Garmin waypoint will
reappear if you have erased it. You will not have any of the tuning
that was performed to calibrate your unit at Garmin so expect poor
initial lockup performance. You will need to have a clear view of the
sky and re-collect a full almanac. This takes about 15 minutes.
- Enter - Hold the enter key down while powering up the unit will
cause a test mode screen to appear. This test screen is used at Garmin
in final testing and calibration of the unit. Warning! Do not use this
screen if your unit can get a lock onto satellites. It is possible
that a real satellite may spoof the test mode into recalibrating the
unit with the wrong data. No permanent damage will be done but you may
experience a little longer lockup times or may even have to do a total
cold start to get it running again. You may also experience continued
longer lockup times for awhile while the unit re-calibrates itself
under use. You can read this document
for a discussion of this issue from Garmin.
If your unit has a
removeable antenna then unplugging the antenna is a good way to ensure
that no lock can be obtained.
The test mode screen can appear automatically if the unit detects a
failure during power up. You can use this mode to verify certain
operations of the unit. For example hitting each key will cause the
corresponding key in the display to darken. Hitting the enter key
twice in a row (on some units it is the page key) will cause a graphic
pixel test which could highlight any bad pixels in your display.
Hitting the same key again will further test the display. Hitting the
key one more time will return to the main test screen. One units that
use the page key to perform this test you can use the quit key to
perform the graphic test backwards. The power/lamp key will show both
an indication and actually light the lamp.
Other displayed entries are specific to internal tests performed in
final test but the temperature (in Celsius), the internal and external
battery voltages, and the gps time can be useful. On the G-III+ and
12Map this mode will also display the version number of the software
which has been removed from the start up screen. Some units report a
Bravo Version which is the version of the hardware. On some units
the status of the power on diagnostics can be viewed here.
While not obvious to an observer the test mode also starts the
interface to emit PVT solutions in Garmin mode on units that support
PVT output. Once started, this mode will continue even after a power
off until you change it in the interface section by selecting "none".
The fact that this command sets Garmin mode may be useful for other
purposes as well. For example this may be a way to recover from a
bad software load or even a corrupt map load.
Emap Startup modes
The Emap supports the same 3 startup modes as other Garmin handhelds
but some of the keys are different.
- Holding enter while powering up enters the test mode as described
above. The temperature display is only in celcius and no external
voltage is shown. You can run the visual screen diagnostics by
holding down the esc key and then tap it to walk through all the
screens.
- Holding down the esc key while powering up will reset the entire
unit and you will lose all of your waypoints, routes, and tracklogs.
There is a warning screen for this startup mode. To continue after a
reset click here.
- Holding down the Find key and powering up forces the auto locate
mode. It also places a couple of numbers in the upper right corner of
the screen but I don't know how to interpret these numbers.
Etrex Startup modes
The etrex also has secret modes for test purposes. Hold the "up" and
"page" keys and then press the "on/off" button to enter this screen.
It behaves similar to the test mode described above and shows some
information that is useful to the user. Note that is has been
reported that the ROM test may show a false failure on this screen
since a factory tester is not attached. You can run the key tests by
pressing each of the keys. You can use the page key to cycle through
all of the display tests. The screen shows the status of the power on
diagnostics plus internal battery voltage and external if present. A
clock display shows seconds, the revision level of the software is
shown, and a thermometer reading shows the internal temperature in
degrees Celsius.
Hold the "up" and "enter" keys and then press the "on/off" button to reset
the entire machine. You will receive a warning prompt. You can avoid
this message using the sequence "Page" plus "Enter" plus "Up" and then press
the "on/off" button. Hold the keys down for 5 seconds to perform the
reset.
The newer etrex units
(venture, legend, and vista) with the "Click Stick" use different keys
to accomplish these tasks but the idea is the same. Holding the click
stick down and then powering up will enter the test screen while
holding the "page" key down and the "click stick" down and then
powering up will reset the unit. You will be prompted with an "are
you sure?" message. On these units holding down the "find" button in
addition to the others will avoid the "are you sure" message. Hold
the buttons for 5 seconds to clear the unit.
Note that the extra key sequence may be an even bigger master reset
but this is not clear to me. A master reset may be needed to clear
the unit if you have left the batteries out for a long period of time
and the unit comes up with the wrong year. Later versions of the
firmware have supposedly addressed this problem. To continue after
a reset click here.
The Legend CX can be forced to Auto Locate by holding down the
upper zoom key while powering up. I suspect this feature is common
to several unit.
Garmin GPS V
To totally reset this unit with firmware prior to 2.20 hold the
Zoom Out and Quit buttons down and then press the power on. All user
data will be lost as will the almanac. To continue after a reset click here. Garmin, in its wisdom, has decided to
disable the reset feature so there is no current way to reset the
unit.
Otherwise the standard secret keys apply. To continue after
a reset click here.
76/Map 76/Map 76S
The reported method to completely reset on of these units hold the
"menu" key and the "quit" key down and then press the "power on" key.
Hold for a full 7 seconds and then release. As with the other units
all information will be lost and you will need to reload the almanac
and all your saved user data to make the unit usable.
For the 76S try this sequence to master reset it. Press and hold
quit, Menu, and the rocker down key. Then press and release the power
on key. release the rocker down and wait for the welcome display.
Now release the quit and menu keys.
Otherwise the standard secret keys apply, including the 72 model.
To continue after a reset click here.
Newer Units
A newer units come out Garmin seems to continue to find new sequences
to try and fool the user. In some cases they have removed the reset
features completely claiming that they can cause problems and mask
problems that need to be fixed. As always use these at you own risk.
On units without a reset sequence Garmin provides a way to set every
setting back to factory defaults.
Geko
The Geko uses the OK key instead of an enter key. It enters test mode
by holding OK and pressing power on. The master reset can be accomplished
by pressing all the keys except the down key for 5 seconds.
To continue after a reset click here.
GPS 60/60CS
Hold enter while powering up to enter test mode. Hold enter and
page while powering up to master reset the unit. The 76C and 76CS
should use the same key strokes as they use the same firmware. To
continue after a reset click here.
GPS 176
The reported reset sequence is press and hold the zoom
out button + the Nav button + the Quit button and then tap
the power button. Continue to hold the zoom out + Nav + Quit
button until the unit comes on. This will reset the GPS 176
C to the factory settings. This reset will erase all user
data like waypoints, routes, etc.
Also note the sequences in the 76 section above which may
have some information for some 176 models.
To continue after a reset click here.
After a reset
If you have to perform a full reset using one of the sequences
shown above you will need to allow the unit to collect a full almanac
before normal can be resumed. First a fix will need to be obtained
which can take from 5 to 10 minutes of leaving your unit outdoors,
stationary, with a good sky view. After the first lock you will need
another 12.5 to 15 minutes to get the almanac reloaded. Check the
date to insure that the information was reloaded properly. Time will
be shown as UTC time since your local time offset was lost in the
reset.
Re-establish all of your preferences such as time zone, daylight
savings flag, etc. Reload all your waypoints and saved routes from
your backup. I do hope you have a backup. WAAS capable receivers will
have to re-establish the WAAS
almanac as well.
Diagnostic Mode
This may be the most useful of the secret modes available on some
of the older Garmin handhelds and, for some users, the hardest to
access. Basically you start the Garmin normally by pressing the power
button and while the opening screen is being display you must press
each of the 4 arrow keys once in any order. If you accomplish this
feat you will be rewarded with a quick switch to the status screen
without waiting for the rest of the time-out. You should notice a -.-
just under the satellite display to confirm your success. If it
doesn't work then power down and try again. It takes a certain rhythm
to be successful. This will not work on G-III or G-III+ units but most
of the information is available on these units in normal mode. On
G-II and G-II+ units this method will only work if you have the unit
set in portrait mode. The etrex and emap do not support this mode.
The beauty of this mode is that you can leave the unit in this mode
while using it. It adds a new Diagnostic menu item and more
information in some of the displays.
- The -.- information on the status
screen will be replaced with a HDOP setting once you have a fix. (HDOP
stands for Horizontal Dilution of Precision and is a measure of the
suitability of the geometry of available satellites to produce an
accurate fix. Numbers below 2.0 mean that the fix is pretty good.)
This is one of the factors used to calculate the estimated position
error (epe) that appears at the top of the page. The EPE number is
proprietary to Garmin but the HDOP number should be similar to one
obtained for any unit since it only depends on the satellite
geometry.
- Really old multiplex units may notice another difference on
the status page. On some units the status bars are solid all of the
time even when ephemeris data is not yet valid. On these units the
hollow bars will appear only in Diagnostic mode. Unfortunately the
new 12CX also has only solid bars and this mode doesn't fix them.
- The position page also has a new entry down near the clock. This
is the current internal temperature in Fahrenheit degrees. On some
units if you have set your preferences to metric this will be displayed
in Celcius.
- Finally the menu page will have a new entry at the bottom. This
"D" can be selected to enter the diagnostic page.
The diagnostic page content will vary depending on which unit you have but
will generally contain diagnostic pass/fail messages at the top of the
screen, the elapsed time for the unit, internal software information,
and finally battery voltage.
- On some units the elapsed time counter can be reset by hitting the
enter key providing an additional timer for the unit. On units that
already have an elapsed time meter in the normal position page then
the one here cannot be reset with the enter key.
- On some units hitting the page key will provide information
about the status of the last several shutdowns.
Pressing quit will return you to the normal screens of the gps but
realize the gps continues to work fine while you are looking at the
diagnostic screen. If you hit goto or mark you will perform these
functions.
It is worth mentioning a little about the elapsed time
meter. Generally this is expected to be the time since the last
factory reset. However, it will be reset by the power-on/mark key
sequence described above and it may be reset by some software
upgrades.
On some units the battery voltage includes both internal and
external voltages. The internal voltage is indicated in .03 volt
increments and seems to have this accuracy. The external voltage is
indicated with the similar precision but does not have this accuracy. The
external voltage has the following decimal setting for each whole
voltage setting: .14, .29, .43, .57, .72, .86, and .00.
Other easter eggs
On some units, mostly older multiplex units, you can redisplay the
world globe that appeared on the opening screen. Change to the map
page and then hit the power-off button but stop before holding it down
long enough to power the unit down. The globe will appear and you can
control the speed of its spinning using the arrow keys.
The III+ can display some icons that are not available on the icon
menu. These are usually found in a downloaded map. For example the
geographic place names are not available except when shown on the map.
However you can use a trick to get these icons into you own waypoints.
Find an entry using one of these waypoints on the screen and then press
enter to convert it to a waypoint. You can now edit the waypoint
values and name to be whatever you wish. These new icons will probably
not be preserved when saved on a pc and re-entered since the pc program
may not support them.
Internal Diagnostic reports
On the etrex models with the click stick you can reach an internal
diagnostic message page which reports stack data and shutdown
data. First change to the trip computer page and press the "zoom out"
key, the "zoom in" key, and the "zoom out" key once again. This will turn
on the diagnostic reports page.
In some other units the diagnostic reports can be reached
from the trip computer page by pressing the cursor keys, up, right, down,
and left in sequence. This is reported to work in the 60C and probably
will work on the 76C as well.
Once your on the diganotic screen the page key will switch to a
screen that shows the condition of the last few shutdowns.
Has anybody found any more?
revision
first published 99/1/4/99
added etrex 00/5/30
add emap 00/6/2
added III+ icon trick 00/7/5
added new etrex models 01/4/9
added 76 and alternate keys for etrex 01/12/22
added V reset 02/03/09
added paragraph on reset recovery 02/07/17
added 72, Geko. 03/03/10
added Legend CX 07/04/05 auto locate
Dale DePriest