Contents: "Disappearing" faults ⇊ Open circuits and short circuits ⇊ Operation of the "MIL" fault detector ⇊
"Disappearing" faults
The term "intermittent failure" means that the system may have failed in the past, but current tests show that it is OK. If the malfunction indicator lamp ("MIL") on the instrument cluster does not illuminate, check for poor connections or loose terminals at all connectors related to the circuit you are troubleshooting. The "MIL" was on but then went out: The failure may be intermittent.
Open circuits and short circuits
"Open circuit" and "short circuit" are common terms in electrical engineering. An open circuit means a broken wire or a loose connection in a connector. A short circuit means accidentally touching a bare ground wire or another bare wire. In simple electronic circuits, this usually results in some electrical component not working at all. In complex electronic systems, (such as ECM computers) this can sometimes mean that the system is working, but not the way it should.
Operation of the "MIL" fault detector
For these models, if you turn the ignition key to the "ON" (II) position without starting the engine, the malfunction indicator lamp will come on for approximately 20 seconds. Then it will go out or flash 5 times under various conditions. This is normal operation of the "MIL" indicator lamp. It indicates the self-diagnosis status of the emission control systems.
The article was taken from the website HondaBook