Russ' Do It Yourself Home Workshop

I’m re-posting these instructions from elearnaid.com with a little clean up as I just used them on my 2002 and 2005 Prii.  Additionally, Art’s Automotive has some good info on repairing the MFD (multi-function display), aka EMV. 

Update 2015-01-26

Oh, by the way, I found you can enable this mode while driving (so far, on my 2005), so it doesn’t appear the parking brake is a requirement to enable inspection mode.

The original instructions from elearnaid.com, with a little cleanup

• The transmission should be in Park with the ignition off.
• Engage the parking brake (this seems to be an interlock of sorts).
• Turn the ignition on
• (2001 – 2003) Turn ignition switch to ON (do not start the engine).
• 2004+ Press the Start button twice (don’t depress the brake and start the engine).
• Push Display button.
• (2001 – 2003) Top rocker to the right of the radio that is labeled “Display.”
• 2004+ Top right button next to the screen that is labeled “Display.”
• "DISPLAY" will now appear in the upper left corner of your screen.)
• Push on the upper left (1) of the display just inside the box, withdraw, push on the lower left of the display (2) and withdraw (see picture for hidden button locations).  Do this slowly and deliberately.
• Do this three times (or more). Keep trying until the screen changes. If the word "Display" in the upper left hand corner of the screen goes away hit the display switch again.

• Push on Menu in upper right of display screen.
• Push on Display Check
• Push on Vehicle Signal Check
• You will see the 12 volt voltage displayed.
• With no electrical accessories on including lights the voltage should be fluctuate between 12.2 and 11.9. The lower the voltage, the less of a charge your battery currently has. If the voltage is low do not proceed as the load test might totally discharge your battery. (If you see a voltage around 13.5-13.8 you are seeing voltage from the high voltage battery being converted to around 13.5-13.8 in an attempt to recharge your battery. This normally does not occur till after you start the engine but might occur earlier if the battery is very drained.)
• You can also test the battery by turning on the headlights, rear window heater and the heater fan. For a new battery the voltage would be around 11.3. If the voltage drops below 10.2 it should definitely be replaced. For voltages in between the lower the voltage, the lower current charge of your battery.

Here are some of the screens displayed on the 2002 Prius.

Here are pictures of the 2005 Prius display.

Audio H/U (Head Unit?) says CHEK.  Press the CHEK button to view the codes and clear them.

A bunch of old codes.  Who knows when they occurred?

Pressing some more CHEK buttons.

Pressing and holding the Code CLR (clear) button to erase the stored codes.

Codes cleared!

More codes to clear!

Display with the headlights turned off.

Display with the headlights lights turned on.