Of course the computer comes back up as soon as the battery is connected
BUT...

the codes can be cleared, and the registers are in a zero state.

Many of the functions that the OBD computer monitors require several drive
cycles before they can accurately register. Thats' why sometimes you can
clear a code, and the light will come back on a day later, rather than right
away.

Some states (like Nevada) REQUIRE that the computer has gone through enough
drive cycles to register accurately. In past years they would allow an
old-fashioned tailpipe sniff test, but no longer.

The reason why is that they don't *actually* test the car anymore.. they
simply communicate with the car's computer and say "how are you running"...
if the car responds "fine, everything is okay" then it passes.

If you notice, the smog cert on OBDII cars doesn't provide the specs for O2,
CO, etc like they do with a manual test... it just says PASSED, or FAILED.

Anyway, like I said earlier... it's entirely possible that it's legit, but
it's also possible that he just cleared the codes so it would't be lit when
folks test drove it...


"Leon van Dommelen" > wrote in message
news
> Nielsen > wrote:
>
> >Hi all,
> >
> >I am about to purchace a 97 Miata Limited Edition which has been
> >sitting in a garage for some time. Seller has to smog and register it
> >before sale.. well... it passed the smog test but the ODB2 computer
> >failed ???
> >Seller claims it failed because he recently gave it a new battery and
> >it needs to be driven a while before the ODB2 computer comes back up -
>
> The computer will come back up as soon as ignition is turned on if
> it is not broke. The seller lied.
>
> If you replace the ECU with an aftermarket one, it would fail OBD
> II. I just happen to know this. That car would be illegal
> to drive, at least here in the USA. But that would suggest a
> big turbo supercharger may have been installed on it in the past.
> Which would suggest lots of wear and tear.
>
> Why not try calling the shop that did the test and ask in what
> way OBD II was failed? If there was no OBD II response, open
> the ECU box behind the passenger seat and have a look.
>
> Leon
>
>
> >is this just a minor issue or should stay away from this one ?
> >
> >Another factor: it has 97K miles on it and he's asking $4K is that
> >reasonable ??
> >
> >Thanks for any answers
> >/Rene
>
> --
> Leon van Dommelen Bozo, the White 96 Sebring Miata .)
> http://www.dommelen.net/miata
> EXIT THE INTERSTATES (Jamie Jensen)