Honda Civic
Check Engine Light
Toyota Camry
Honda Civic EX

What could be wrong when the maintenance required light comes on in a 1998 civic ex?

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2006-08-14 06:28:37

.........................ANYTHING THE COMPUTER IS HOOKED TO CAN

TURN ON THE LIGHT..................................... The

M.I.L.(Maintenance Indicator Light) is a version of the same thing

known as a S.E.S.(Service Engine Soon) light, and is a means

whereby an abnormal condition which the onboard computer has

detected causes a visual signal to the operator to show. Whenever

the computer receives a signal from a sensor that is out-of-range

from its programming, this lamp will illuminate; and, so long as

the condition persists, and does not correct itself, the light will

stay lit--- depicting that a 'hard code' has set in computer

memory. Whenever a scan-tool is hooked to the diagnostic link in

the vehicle, the primary reason is to 'read the codes'; which,

interpreted, means extracting the recorded code numbers for the

purpose of identifying what the computer has detected, in order to

isolate a problem condition and effect a proper repair. When this

light comes on, it is a sign that something has occurred which the

computer 'thinks' is wrong. The reason for the computer to 'think'

this may be a legitimate problem; or, some condition which IS

normal(but unanticipated) may have caused it. For example: If the

Oxygen sensor is reading high or low, this could indicate a vacuum

leak, a fuel problem, a wiring problem, a clogged air filter, an

exhaust leak, high fuel pressure, a bad sensor, etc.; and, if the

variation in signal from this sensor is small, the same code could

set. The light would come on. And, the 'problem' may be that the

driver is making little use of the accelerator, traveling on level

road, on a highway, at constant speed, in the middle of the night.

This would keep the oxygen sensor's voltage in the same range for a

period of time not normally seen. The range is a GOOD range; but,

the fact that it is out of the norm by virtue of a time factor

would set a code. In such a case, the computer was 'fooled'. This

is why it is important to have the codes read by someone who can

make the determination whether the codes are a sign of trouble or

not; and, what kind of trouble may be showing up in the displaying

of certain codes.


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