First hold the the MODE button and the UP ARROW button together and turn on the
The last display will cause the WHOLE display to GAUGE TEST itself, by lighting up all internal lights and move all temp, tacho,speedo, and fuel to middle range, extra lights like LPG and ABS will be tested by this and plus the buzzer will sound as well.
The last step and this is to reset your computer back the normal DISPLAY, this is done by turning off your ignition or holding both up and down arrow together with DISPLAY in NORMAL MODE straight away, or just restart the engine when your ready will bring it up in NORMAL MODE.