Check engine light won't shut off

Please help...
I have a 1998 honda prelude. My check engine light has been on for 8
months... The mechanic says it's the O2 sensor (before catalytic
converter). I've replaced it with an OEM and unplug my battery to reset
the computer, but the light comes on the next day (happens everytime).
Does anyone know what's wrong or what I should do????
thanx in advance

 

Might be a totally different problem. What you're doing is not smart, and
you could cause further (very expensive) damage by ignoring the light.

If you're in the US, take it to AutoZone and get the code read for free.
Report back here.

 

And you assume that because the O2 sensor was replaced that it can't possibly
be at fault? Silly you! It could be a defective part or it could have been
installed incorrectly. Why, pray tell, haven't you brought it back to the
mechanic?

If you bought a tire and it was flat the next day, would you spend the next
week driving on the flat tire and discussing it on usenet instead of just
taking the damn thing back to where you bought it?

 

Hi,
I've taken it to an automotive shop... and they've hooked it up to
their computer... the mechanic said that he didn't fine a code so he
doesn't know what the problem is so all he could do is reset the code...
however, the light came back on later that day... he said that I needed to
find a shop that is capable of running a complete diagnostic... does
AutoZone have this capability???
thanx again,

 

if the light's coming on but the tech is not getting a code, it's one of
3 problems:

1. your tech doesn't know what they're doing.
2. there is something wrong with your ecu.
3. you're imagining it.

let's assume that 3 is not the case, and that 2 is most unlikely. that
leaves you the option of finding a different tech that is competent -
the ecu does /not/ show the light unless it's registered a fault code,
so the code /has/ to be stored. consider a dealer if this really is a
persistent issue.

 

Hi,
That's true "aznomad"... I replaced the O2 sensor at one shop and the
mechanic cut off the light... 3 days later, got it diagnose at another
when it came back on... the second shop said that they could not find
anything wrong but they can cut the light off none the less... however, it
came on again and the second shop said that I never to get a "complete"
diagnostic from an $8000 machine... what would you guys recommand???
thanx

 

If that mechanic needs an $8000 machine to replace the skills of a 100IQ
mechanic with 2 years experience, he should be fired.

The light won't come on without there being codes to report. Unless the
computer itself is fried which is very unlikely.

If the second shop can't figure out how to read out the codes, then you've
somehow managed to find two incompetant shops.

Maybe the third one will be the charm.

As another poster mentioned, if you live in North America, find an autozone and
have them read out the codes for you.

 

This means the code is probably a Honda "enhanced" code (P1, P2, P3, etc.)
and his reader won't see it.

You need to find a mechanic with a reader that will display Honda enhanced
codes.

Not quite, you just need a shop that has spent $600 for a REAL code reader.

Yup. But not for free if you're in California.

 

Hi,
Ok... I'll do that... thank you so much for your help.
thanx again...

 

why is california so "speshul"?

i ended up spending $99 on an actron code reader.

 

Mechanics who can't diagnose a problem when there's a glowing Check
Engine light are absolutely incompetent, and even with a $200 machine
they should be able to narrow it down considerably by interpreting all
the sensor readings while the engine runs.

Can't even newer Hondas blink out a basic set of diagnostic codes
without the use of any equipment? You may want to check Mitchell and
factory manuals at a library for this and other information. There are
probably 200-500 pages of diagnostic tables for the fuel/emissions
system alone, and almost all component tests can be performed with a
cheap volt/ohm meter

 

Mechanics who can't diagnose a problem when there's a glowing Check
Engine light are absolutely incompetent, and even with a $200 machine
they should be able to narrow it down considerably by interpreting all
the sensor readings while the engine runs.

Can't even newer Hondas blink out a basic set of diagnostic codes
without the use of any equipment? You may want to check Mitchell and
factory manuals at a library for this and other information. There are
probably 200-500 pages of diagnostic tables for the fuel/emissions
system alone, and almost all component tests can be performed with a
cheap volt/ohm meter

 

Did you check or replace the gas cap? One that is not seating properly can
cause the check engine light to come on!

 

Hi,I had the same problem with my1995 Honda Odyssey.Check you
exhaust manifold for any crack's, look close, if there is even a tin
crack in it or a leak in the mounting gasket to the engine anywher
,the check engine will come on and stay on.Hope this might help?

Huppy3