Electronic Control System: Self-diagnosis
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Honda Odyssey, 2003 Honda Odyssey, 2002 Honda Odyssey, 2001 Honda Odyssey, and 2000 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.
When an abnormality occurs in the signal from a sensor, the PCM supplies ground for the malfunction indicator lamp (MIL) and stores the diagnostic trouble code (DTC) in erasable memory. When the ignition is first turned on, the PCM supplies ground to the MIL for 2 seconds ('99-01 models) or for 15 to 20 seconds ('02-04 models) to check the MIL bulb condition.