Ferrari Mailing List: Re: Diagnostic Problem - 1995 348 Spyder

[Dennis Liu (bigheaddennis]

Dr. Steve wrote:

>The indicator is the "Check Engine 5/8" light, which first illuminated only
at idle and then only for a short period of time ("sporadic error pg. C11
Owner's Manual) and a little later on the same light illuminated and then
did not go out ("static error, ibid). The manual refers to an OBD system and
explains which button should be pushed to "pull" the diagnostic codes near
the  ECU, but makes no reference as to where to read the codes, how they are
read or what they mean.
 
There is also a great deal of ambiguity as to exactly what a "sporadic" or
a "static" error indication in the Check Engine 5/8 would possibly
indicate.
 
Additional information. All gauges read within normal parameters and no
other caution or warning lights are illuminated. The "sporadic" indications
first occurred en route to where I could access a lift to change out the
battery. 
There were no indications of any errors during or immediately after the
installation of the new battery and I had initially just wrote off the
indication as a voltage/amperage issue with the old battery. The car starts
up  well, but then stalls out as if it would not reset to a fast(er) idle
until it  warms up. Restarts immediately and then will run as long as the
accelerator  pedal is depressed to raise the idle speed by several hundred
rpm. Restarts  correctly when hot. The "Check Engine 5/8" light
re-illuminates upon start up  and remains on in the "static error" mode.
 
<remainder snipped; also, ridiculously long sig snipped>

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You almost certainly have a bad engine ECU.  They come in pairs.  Lots and
lots of failures of these components in the 348 (and in the 355 as well, but
less common).  Failure mode includes major loss of power, resulting from the
car running on four cylinders.  If this happens, do not drive the car.  

Side-of-the-road cure:  kill the battery to reset the ECUs, restart, and
problem may have gone away.

Diagnosis:  swap ECUs from side to side.  If the error now shows on the 1/4
bank, you know that you've got a bad ECU.

Failure mode:  housing around ECU cracks from strain and heat, then moisture
seeps in, causing occasional errors.

Fix:  replace ECU.  If you're cheap and handy, you can try sealing the
cracks with a silicone sealant, but that might only buy you time.  The part
is not cheap (last time I checked, about 6 years ago, it was close to $300,
surely more, maybe much more now), but labor is DIY, at least.

Vty,

--Dennis