Entering Diagnostic Mode With Super Monitor Display

WARNING: This page is about a different car, the 1987 Toyota Supra. However, it is still accessible from the selected car via links, so may be relevant.

Prior to entering diagnostic mode, ensure that engine is at normal operating temperature, battery voltage above 11 volts, transmission in "P" or "N", throttle valve fully closed and A/C off.
Turn ignition switch to the ON position, but DO NOT start engine. Simultaneously push and hold in "SELECT" key and "INPUT M" key for at least 3 seconds. See Figure. The letters "DIAG" will appear on screen.
After a short pause, hold in "SET" key for at least 3 seconds. If system is normal, "ENG - OK" will appear on screen. If there is a malfunction, the code number for the malfunction will appear on the screen. In the event of 2 or more numbers, there will be a 3 seconds pause between each number.